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Expanding treatment options alongside ensuring high coverage of mass drug administration can accelerate progress in elimination of lymphatic filariasis, say Sabine Specht and colleagues

A mass test and treat campaign (MTAT) using rapid diagnostic tests (RDTs) and artemether-lumefantrine (AL) was conducted in Southern Zambia in 2012 and 2013 to reduce the parasite reservoir and progress towards malaria elimination.,Through this intervention, community health workers (CHWs) tested all household members with rapid diagnostic tests (RDTs) and provided treatment to those that tested positive.,A qualitative study was undertaken to understand CHW and community perceptions regarding the MTAT campaign.,A total of eight focus groups and 33 in-depth and key informant interviews were conducted with CHWs, community members and health centre staff that participated in the MTAT.,Interviews and focus groups with CHWs and community members revealed that increased knowledge of malaria prevention, the ability to reach people who live far from health centres, and the ability of the MTAT campaign to reduce the malaria burden were the greatest perceived benefits of the campaign.,Conversely, the primary potential barriers to effectiveness included refusals to be tested, limited adherence to drug regimens, and inadequate commodity supply.,Study respondents generally agreed that MTAT services were scalable outside of the study area but would require greater involvement from district and provincial medical staff.,These findings highlight the importance of increased community sensitization as part of mass treatment campaigns for improving campaign coverage and acceptance.,Further, they suggest that communication channels between the Ministry of Health, National Malaria Control Centre and Medical Stores Limited may need to be improved so as to ensure there is consistent supply and management of commodities.,Continued capacity building of CHWs and health facility supervisors is critical for a more effective programme and sustained progress towards malaria elimination.

Next-generation sequencing (NGS) technologies are increasingly being used to address a diverse range of biological and epidemiological questions.,The current understanding of malaria transmission dynamics and parasite movement mainly relies on the analyses of epidemiologic data, e.g. case counts and self-reported travel history data.,However, travel history data are often not routinely collected or are incomplete, lacking the necessary level of accuracy.,Although genetic data from routinely collected field samples provides an unprecedented opportunity to track the spread of malaria parasites, it remains an underutilized resource for surveillance due to lack of local awareness and capacity, limited access to sensitive laboratory methods and associated computational tools and difficulty in interpreting genetic epidemiology data.,In this review, the potential roles of NGS in better understanding of transmission patterns, accurately tracking parasite movement and addressing the emerging challenges of imported malaria in low transmission settings of sub-Saharan Africa are discussed.,Furthermore, this review highlights the insights gained from malaria genomic research and challenges associated with integrating malaria genomics into existing surveillance tools to inform control and elimination strategies.

Despite the biological plausibility of hotspots fueling malaria transmission, the evidence to support this concept has been mixed.,If transmission spreads from high burden to low burden households in a consistent manner, then this could have important implications for control and elimination program development.,Data from a longitudinal cohort in The Gambia was analyzed.,All consenting individuals residing in 12 villages across the country were sampled monthly from June (dry season) to December 2013 (wet season), in April 2014 (mid dry season), and monthly from June to December 2014.,A study nurse stationed within each village recorded passively detected malaria episodes between visits.,Plasmodium falciparum infections were determined by polymerase chain reaction and analyzed using a geostatistical model.,Household-level observed monthly incidence ranged from 0 to 0.50 infection per person (interquartile range = 0.02-0.10) across the sampling months, and high burden households exist across all study villages.,There was limited evidence of a spatio-temporal pattern at the monthly timescale irrespective of transmission intensity.,Within-household transmission was the most plausible hypothesis examined to explain the observed heterogeneity in infections.,Within-village malaria transmission patterns are concentrated in a small proportion of high burden households, but patterns are stochastic regardless of endemicity.,Our findings support the notion of transmission occurring at the household and village scales but not the use of a targeted approach to interrupt spreading of infections from high to low burden areas within villages in this setting.,The online version of this article (10.1186/s12916-018-1141-4) contains supplementary material, which is available to authorized users.

Malaria in pregnancy (MiP) is an important public health problem across sub-Saharan Africa.,The package of measures for its control in Ghana in the last 20 years include regular use of long-lasting insecticide-treated bed nets (LLINs), directly-observed administration (DOT) of intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) and prompt and effective case management of MiP.,Unfortunately, Ghana like other sub-Saharan African countries did not achieve the reset Abuja targets of 100% of pregnant women having access to IPTp and 100% using LLINs by 2015.,This ethnographic study explored how healthcare managers dealt with existing MiP policy implementation challenges and the consequences on IPTp-SP uptake and access to maternal healthcare.,The study collected date using non-participant observations, conversations, in-depth interviews and case studies in eight health facilities and 12 communities for 12 months in two Administrative regions in Ghana.,Healthcare managers addressed frequent stock-outs of malaria programme drugs and supplies from the National Malaria Control Programme and delayed reimbursement from the NHIS, by instituting co-payment, rationing and prescribing drugs for women to buy from private pharmacies.,This ensured that facilities had funds to pay creditors, purchase drugs and supplies for health service delivery.,However, it affected their ability to enforce DOT and to monitor adherence to treatment.,Women who could afford maternal healthcare and MiP services and those who had previously benefitted from such services were happy to access uninterrupted services.,Women who could not maternal healthcare services resorted to visiting other sources of health care, delaying ANC and skipping scheduled ANC visits.,Consequently, some clients did not receive the recommended 5 + doses of SP, others did not obtain LLINs early and some did not obtain treatment for MiP.,Healthcare providers felt frustrated whenever they could not provide comprehensive care to women who could not afford comprehensive maternal and MiP care.,For Ghana to achieve her goal of controlling MiP, the Ministry of Health and other supporting institutions need to ensure prompt reimbursement of funds, regular supply of programme drugs and medical supplies to public, faith-based and private health facilities.

About 25% of pregnant women in malaria-endemic areas are infected with malaria and this accounts for about 15% of maternal deaths globally.,Intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) is one of the main strategies for prevention of malaria in pregnancy.,A new recommendation was made by the World Health Organization (WHO) that at least three doses of IPTp-SP should be administered before delivery.,This study sought to determine the factors influencing adherence to the new IPTp-SP policy in Keta District, Volta region, Ghana.,A cross-sectional quantitative study among 375 nursing mothers at four selected health facilities in Keta district, Ghana was conducted using a structured questionnaire to interview participants.,Sampling proportionate to the size of facility was used to determine the number of nursing mothers from each facility based on the caseload.,For each facility systematic random sampling was used to select eligible nursing mothers.,Data was analyzed using STATA 15.,Chi-square was used to test bivariate association between categorical variables and adherence.,Logistic regression analysis was used to examine sociodemographic, individual and institutional factors influencing adherence to IPTp-SP.,About 82.1% of participants adhered to the WHO policy recommendations of at least three doses of IPTp-SP.,However, only 17.1% received Ghana’s five dose coverage recommendation.,The proportion of IPTp-SP coverage for IPTp1 was 98.9%; IPTp2 95.5%; IPTp3 80.8%; IPTp4 39.5%; IPTp5 17.1%.,Adherence to IPTp-SP was satisfactory according to WHO’s policy recommendation, however, majority of the participants had less than the five doses recommended in Ghana.,Number of Antenatal Care (ANC) visits and knowledge of malaria were the main determinants of adherence to IPTp-SP.

Since the year 2000, a concerted campaign against malaria has led to unprecedented levels of intervention coverage across sub-Saharan Africa.,Understanding the effect of this control effort is vital to inform future control planning.,However, the effect of malaria interventions across the varied epidemiological settings of Africa remains poorly understood owing to the absence of reliable surveillance data and the simplistic approaches underlying current disease estimates.,Here we link a large database of malaria field surveys with detailed reconstructions of changing intervention coverage to directly evaluate trends from 2000 to 2015 and quantify the attributable effect of malaria disease control efforts.,We found that Plasmodium falciparum infection prevalence in endemic Africa halved and the incidence of clinical disease fell by 40% between 2000 and 2015.,We estimate that interventions have averted 663 (542-753 credible interval) million clinical cases since 2000.,Insecticide-treated nets, the most widespread intervention, were by far the largest contributor (68% of cases averted).,Although still below target levels, current malaria interventions have substantially reduced malaria disease incidence across the continent.,Increasing access to these interventions, and maintaining their effectiveness in the face of insecticide and drug resistance, should form a cornerstone of post-2015 control strategies.

The RTS,S/AS01 malaria vaccine targets the circumsporozoite protein, inducing antibodies associated with the prevention of Plasmodium falciparum infection.,We assessed the association between anti-circumsporozoite antibody titres and the magnitude and duration of vaccine efficacy using data from a phase 3 trial done between 2009 and 2014.,Using data from 8922 African children aged 5-17 months and 6537 African infants aged 6-12 weeks at first vaccination, we analysed the determinants of immunogenicity after RTS,S/AS01 vaccination with or without a booster dose.,We assessed the association between the incidence of clinical malaria and anti-circumsporozoite antibody titres using a model of anti-circumsporozoite antibody dynamics and the natural acquisition of protective immunity over time.,RTS,S/AS01-induced anti-circumsporozoite antibody titres were greater in children aged 5-17 months than in those aged 6-12 weeks.,Pre-vaccination anti-circumsporozoite titres were associated with lower immunogenicity in children aged 6-12 weeks and higher immunogenicity in those aged 5-17 months.,The immunogenicity of the booster dose was strongly associated with immunogenicity after primary vaccination.,Anti-circumsporozoite titres wane according to a biphasic exponential distribution.,In participants aged 5-17 months, the half-life of the short-lived component of the antibody response was 45 days (95% credible interval 42-48) and that of the long-lived component was 591 days (557-632).,After primary vaccination 12% (11-13) of the response was estimated to be long-lived, rising to 30% (28-32%) after a booster dose.,An anti-circumsporozoite antibody titre of 121 EU/mL (98-153) was estimated to prevent 50% of infections.,Waning anti-circumsporozoite antibody titres predict the duration of efficacy against clinical malaria across different age categories and transmission intensities, and efficacy wanes more rapidly at higher transmission intensity.,Anti-circumsporozoite antibody titres are a surrogate of protection for the magnitude and duration of RTS,S/AS01 efficacy, with or without a booster dose, providing a valuable surrogate of effectiveness for new RTS,S formulations in the age groups considered.,UK Medical Research Council.

The blood-stage malaria vaccine FMP2.1/AS02A, comprised of recombinant Plasmodium falciparum apical membrane antigen 1 (AMA1) and the adjuvant system AS02A, had strain-specific efficacy against clinical malaria caused by P. falciparum with the vaccine strain 3D7 AMA1 sequence.,To evaluate a potential correlate of protection, we measured the ability of participant sera to inhibit growth of 3D7 and FVO strains in vitro using high-throughput growth inhibition assay (GIA) testing.,Sera from 400 children randomized to receive either malaria vaccine or a control rabies vaccine were assessed at baseline and over two annual malaria transmission seasons after immunization.,Baseline GIA against vaccine strain 3D7 and FVO strain was similar in both groups, but more children in the malaria vaccine group than in the control group had 3D7 and FVO GIA activity ≥15% 30 days after the last vaccination (day 90) (49% vs. 16%, p<0.0001; and 71.8% vs.,60.4%, p = 0.02).,From baseline to day 90, 3D7 GIA in the vaccine group was 7.4 times the mean increase in the control group (p<0.0001).,In AMA1 vaccinees, 3D7 GIA activity subsequently returned to baseline one year after vaccination (day 364) and did not correlate with efficacy in the extended efficacy time period to day 730.,In Cox proportional hazards regression models with time-varying covariates, there was a slight suggestion of an association between 3D7 GIA activity and increased risk of clinical malaria between day 90 and day 240.,We conclude that vaccination with this AMA1-based malaria vaccine increased inhibition of parasite growth, but this increase was not associated with allele-specific efficacy in the first malaria season.,These results provide a framework for testing functional immune correlates of protection against clinical malaria in field trials, and will help to guide similar analyses for next-generation malaria vaccines.,Clinical trials registry: This clinical trial was registered on clinicaltrials.gov, registry number NCT00460525.

Pedro Alonso and colleagues introduce the Malaria Eradication Research Agenda (malERA) initiative and the set of articles published in this PLoS Medicine Supplement that distill the research questions key to malaria eradication.,The interruption of malaria transmission worldwide is one of the greatest challenges for international health and development communities.,The current expert view suggests that, by aggressively scaling up control with currently available tools and strategies, much greater gains could be achieved against malaria, including elimination from a number of countries and regions; however, even with maximal effort we will fall short of global eradication.,The Malaria Eradication Research Agenda (malERA) complements the current research agenda-primarily directed towards reducing morbidity and mortality-with one that aims to identify key knowledge gaps and define the strategies and tools that will result in reducing the basic reproduction rate to less than 1, with the ultimate aim of eradication of the parasite from the human population.,Sustained commitment from local communities, civil society, policy leaders, and the scientific community, together with a massive effort to build a strong base of researchers from the endemic areas will be critical factors in the success of this new agenda.

Control initiatives have successfully reduced the prevalence and intensity of schistosomiasis transmission in several localities around the world.,However, individuals that release low numbers of eggs in their feces may not be detected by classical methods that are limited by low sensitivity.,Given that accurate estimates of prevalence are key to implementing planning control actions for the elimination of schistosomiasis, new diagnostic tools are needed to effectively monitor infections and confirm transmission interruption.,The World Health Organization recommends the Kato-Katz (KK) thick smear as a parasitological test for epidemiological surveys, even though this method has been demonstrated to underestimate prevalence when egg burdens are low.,The point-of-care immunodiagnostic for detecting schistosome cathodic circulating antigen (POC-CCA) method has been proposed as a more sensitive substitute for KK in prevalence estimations.,An alternative diagnostic, the Helmintex (HTX) method, isolates eggs from fecal samples with the use of paramagnetic particles in a magnetic field.,Here, a population-based study involving 461 individuals from Candeal, Sergipe State, Brazil, was conducted to evaluate these three methods comparatively by latent class analysis (LCA).,The prevalence of schistosomiasis mansoni was determined to be 71% with POC-CCA, 40.% with HTX and 11% with KK.,Most of the egg burdens of the individuals tested (70%) were < 1 epg, thereby revealing a dissociation between prevalence and intensity in this locality.,Therefore, the present results confirm that the HTX method is a highly sensitive egg detection procedure and support its use as a reference method for diagnosing intestinal schistosomiasis and for comparative evaluation of other tests.

The Kato-Katz technique is widely used for the diagnosis of Schistosoma mansoni, but shows low sensitivity in light-intensity infections.,We assessed the accuracy of a commercially available point-of-care circulating cathodic antigen (POC-CCA) cassette test for the diagnosis of S. mansoni in preschool-aged children before and after praziquantel administration.,A 3-week longitudinal survey with a treatment intervention was conducted in Azaguié, south Côte d'Ivoire.,Overall, 242 preschoolers (age range: 2 months to 5.5 years) submitted two stool and two urine samples before praziquantel administration, and 86 individuals were followed-up posttreatment.,Stool samples were examined with duplicate Kato-Katz thick smears for S. mansoni.,Urine samples were subjected to POC-CCA cassette test for S. mansoni, and a filtration method for S. haematobium diagnosis.,Before treatment, the prevalence of S. mansoni, as determined by quadruplicate Kato-Katz, single CCA considering ‘trace’ as negative (t−), and single CCA with ‘trace’ as positive (t+), was 23.1%, 34.3% and 64.5%, respectively.,Using the combined results (i.e., four Kato-Katz and duplicate CCA(t−)) as diagnostic ‘gold’ standard, the sensitivity of a single Kato-Katz, a single CCA(t−) or CCA(t+) was 28.3%, 69.7% and 89.1%, respectively.,Three weeks posttreatment, the sensitivity of a single Kato-Katz, single CCA(t−) and CCA(t+) was 4.0%, 80.0% and 84.0%, respectively.,The intensity of the POC-CCA test band reaction was correlated with S. mansoni egg burden (odds ratio = 1.2, p = 0.04).,A single POC-CCA cassette test appears to be more sensitive than multiple Kato-Katz thick smears for the diagnosis of S. mansoni in preschool-aged children before and after praziquantel administration.,The POC-CCA cassette test can be recommended for the rapid identification of S. mansoni infections before treatment.,Additional studies are warranted to determine the usefulness of POC-CCA for assessing drug efficacy and monitoring the impact of control interventions.

Schistosomiasis is the most widespread water-based disease in sub-Saharan Africa.,Transmission is governed by the spatial distribution of specific freshwater snails that act as intermediate hosts and human water contact patterns.,Remote sensing data have been utilized for spatially explicit risk profiling of schistosomiasis.,We investigated the potential of remote sensing to characterize habitat conditions of parasite and intermediate host snails and discuss the relevance for public health.,We employed high-resolution remote sensing data, environmental field measurements, and ecological data to model environmental suitability for schistosomiasis-related parasite and snail species.,The model was developed for Burkina Faso using a habitat suitability index (HSI).,The plausibility of remote sensing habitat variables was validated using field measurements.,The established model was transferred to different ecological settings in Côte d’Ivoire and validated against readily available survey data from school-aged children.,Environmental suitability for schistosomiasis transmission was spatially delineated and quantified by seven habitat variables derived from remote sensing data.,The strengths and weaknesses highlighted by the plausibility analysis showed that temporal dynamic water and vegetation measures were particularly useful to model parasite and snail habitat suitability, whereas the measurement of water surface temperature and topographic variables did not perform appropriately.,The transferability of the model showed significant relations between the HSI and infection prevalence in study sites of Côte d’Ivoire.,A predictive map of environmental suitability for schistosomiasis transmission can support measures to gain and sustain control.,This is particularly relevant as emphasis is shifting from morbidity control to interrupting transmission.,Further validation of our mechanistic model needs to be complemented by field data of parasite- and snail-related fitness.,Our model provides a useful tool to monitor the development of new hotspots of potential schistosomiasis transmission based on regularly updated remote sensing data.

After many years of neglect, schistosomiasis control is going to scale.,The strategy of choice is preventive chemotherapy, that is the repeated large-scale administration of praziquantel (a safe and highly efficacious drug) to at-risk populations.,The frequency of praziquantel administration is based on endemicity, which usually is defined by prevalence data summarized at an arbitrarily chosen administrative level.,For an ensemble of 29 West and East African countries, we determined the annualized praziquantel treatment needs for the school-aged population, adhering to World Health Organization guidelines.,Different administrative levels of prevalence aggregation were considered; country, province, district, and pixel level.,Previously published results on spatially explicit schistosomiasis risk in the selected countries were employed to classify each area into distinct endemicity classes that govern the frequency of praziquantel administration.,Estimates of infection prevalence adjusted for the school-aged population in 2010 revealed that most countries are classified as moderately endemic for schistosomiasis (prevalence 10-50%), while four countries (i.e., Ghana, Liberia, Mozambique, and Sierra Leone) are highly endemic (>50%).,Overall, 72.7 million annualized praziquantel treatments (50% confidence interval (CI): 68.8-100.7 million) are required for the school-aged population if country-level schistosomiasis prevalence estimates are considered, and 81.5 million treatments (50% CI: 67.3-107.5 million) if estimation is based on a more refined spatial scale at the provincial level.,Praziquantel treatment needs may be over- or underestimated depending on the level of spatial aggregation.,The distribution of schistosomiasis in Ethiopia, Liberia, Mauritania, Uganda, and Zambia is rather uniform, and hence country-level risk estimates are sufficient to calculate treatment needs.,On the other hand, countries like Burkina Faso, Mali, Mozambique, Sudan, and Tanzania show large spatial heterogeneity in schistosomiasis risk, which should be taken into account for calculating treatment requirements.

Despite decreases in incidence and related mortality, malaria remains a major public health challenge in the Greater Mekong Sub-region (GMS).,The emergence of artemisinin resistance threatens these gains and has prompted efforts to accelerate elimination in the region.,In the GMS, transmission now clusters in hotspots along international borders and among high-risk populations, including forest-goers.,To eliminate malaria in the region, interventions must target such hard-to-reach populations.,This review provides a comprehensive overview of the qualitative research on behaviours and perceptions that influence uptake of and adherence to malaria interventions among forest-goers in the GMS.,A systematic search strategy was used to identify relevant sources, including database (OVID SP, PubMed, ISI Web of Knowledge) and bibliographic searches.,Relevant findings from qualitative research methods were extracted and thematic analysis undertaken.,Of 268 sources retrieved in searches twenty-two were reviewed.,Most reported studies were conducted in Cambodia (n = 10), and were published after 2014 (n = 16).,Four major themes emerged that are particularly relevant to the design of intervention packages targeted at forest-goers: (1) understanding of malaria and perceived risk; (2) preventive measures used when visiting the forest; (3) behaviours that put forest-goers at risk of infection; and, (4) malaria-related treatment seeking.,There were notable differences across the reviewed articles that suggest the need for a locally tailored approach.,A more detailed characterization of forest activities is needed but research on this topic raises methodological challenges.,Current vector control measures have limitations, with use of insecticidal-treated nets, hammocks and repellents influenced by the type of forest activities and the characteristics of these measures.,In contrast, anti-malarial drugs, for example, as chemoprophylaxis, hold promise but require further evaluation.,The online version of this article (10.1186/s12936-019-2666-5) contains supplementary material, which is available to authorized users.

Plasmodium vivax is highly endemic in the lowlands of Papua New Guinea and accounts for a large proportion of the malaria cases in children less than 5 years of age.,We collected 2117 blood samples at 2-monthly intervals from a cohort of 268 children aged 1 to 4.5 years and estimated the diversity and multiplicity of P. vivax infection.,All P. vivax clones were genotyped using the merozoite surface protein 1 F3 fragment (msp1F3) and the microsatellite MS16 as molecular markers.,High diversity was observed with msp1F3 (H E = 88.1%) and MS16 (H E = 97.8%).,Of the 1162 P. vivax positive samples, 74% harbored multi-clone infections with a mean multiplicity of 2.7 (IQR = 1-3).,The multiplicity of P. vivax infection increased slightly with age (P = 0.02), with the strongest increase in very young children.,Intensified efforts to control malaria can benefit from knowledge of the diversity and MOI both for assessing the endemic situation and monitoring the effects of interventions.

Dihydroartemisinin-piperaquine is an effective and well tolerated artemisinin-based combination therapy that has been assessed extensively for the prevention and treatment of malaria.,Piperaquine, similar to several structurally related antimalarials currently used, can prolong cardiac ventricular repolarisation duration and the electrocardiographic QT interval, leading to concerns about its proarrhythmic potential.,We aimed to assess the risk of potentially lethal iatrogenic ventricular arrhythmias in individuals receiving dihydroartemisinin-piperaquine.,We did a systematic review and Bayesian meta-analysis.,We searched clinical bibliographic databases (last on May 24, 2017) for studies of dihydroartemisinin-piperaquine in human beings.,Further unpublished studies were identified with the WHO Evidence Review Group on the Cardiotoxicity of Antimalarials.,We searched for articles containing “dihydroartemisinin-piperaquine” as title, abstract, or subject heading keywords, with synonyms and variant spellings as additional search terms.,We excluded animal studies, but did not apply limits on language or publication date.,Eligible studies were prospective, randomised, controlled trials or cohort studies in which individuals received at least one 3-day treatment course of dihydroartemisinin-piperaquine for mass drug administration, preventive therapy, or case management of uncomplicated malaria, with follow-up over at least 3 days.,At least two independent reviewers screened titles, abstracts, and full texts, agreed study eligibility, and extracted information about study and participant characteristics, adverse event surveillance methodology, dihydroartemisinin-piperaquine exposures, loss-to-follow up, and any deaths after dihydroartemisinin-piperaquine treatment into a standardised database.,The risk of sudden unexplained death after dihydroartemisinin-piperaquine with 95% credible intervals (CI) generated by Bayesian meta-analysis was compared with the baseline rate of sudden cardiac death.,Our search identified 94 eligible primary studies including data for 197 867 individuals who had received dihydroartemisinin-piperaquine: 154 505 in mass drug administration programmes; 15 188 in 14 studies of repeated courses in preventive therapies and case management of uncomplicated malaria; and 28 174 as single-course treatments of uncomplicated malaria in 76 case-management studies.,There was one potentially drug-related sudden unexplained death: a healthy woman aged 16 in Mozambique who developed heart palpitations several hours after the second dose of dihydroartemisinin-piperaquine and collapsed and died on the way to hospital (no autopsy or ECG was done).,The median pooled risk estimate of sudden unexplained death after dihydroartemisinin-piperaquine was 1 in 757 950 (95% CI 1 in 2 854 490 to 1 in 209 114).,This risk estimate was not higher than the baseline rate of sudden cardiac death (0·7-11·9 per 100 000 person-years or 1 in 1 714 280 to 1 in 100 835 over a 30-day risk period).,The risk of bias was low in most studies and unclear in a few.,Dihydroartemisinin-piperaquine was associated with a low risk of sudden unexplained death that was not higher than the baseline rate of sudden cardiac death.,Concerns about repolarisation-related cardiotoxicity need not limit its current use for the prevention and treatment of malaria.,Wellcome Trust, UK Medical Research Council, WHO, Bill & Melinda Gates Foundation, and University of Oxford.

Chloroquine is the first-line treatment for Plasmodium vivax malaria in most endemic countries, but resistance is increasing.,Monitoring of antimalarial efficacy is essential, but in P vivax infections the assessment of treatment efficacy is confounded by relapse from the dormant liver stages.,We systematically reviewed P vivax malaria treatment efficacy studies to establish the global extent of chloroquine resistance.,We searched Medline, Web of Science, Embase, and the Cochrane Database of Systematic Reviews to identify studies published in English between Jan 1, 1960, and April 30, 2014, which investigated antimalarial treatment efficacy in P vivax malaria.,We excluded studies that did not include supervised schizonticidal treatment without primaquine.,We determined rates of chloroquine resistance according to P vivax malaria recurrence rates by day 28 whole-blood chloroquine concentrations at the time of recurrence and study enrolment criteria.,We identified 129 eligible clinical trials involving 21 694 patients at 179 study sites and 26 case reports describing 54 patients.,Chloroquine resistance was present in 58 (53%) of 113 assessable study sites, spread across most countries that are endemic for P vivax.,Clearance of parasitaemia assessed by microscopy in 95% of patients by day 2, or all patients by day 3, was 100% predictive of chloroquine sensitivity.,Heterogeneity of study design and analysis has confounded global surveillance of chloroquine-resistant P vivax, which is now present across most countries endemic for P vivax.,Improved methods for monitoring of drug resistance are needed to inform antimalarial policy in these regions.,Wellcome Trust (UK).

Malaria is one of the most devastating infectious diseases of humans.,It is problematic clinically and economically as it prevails in poorer countries and regions, strongly hindering socioeconomic development.,The causative agents of malaria are unicellular protozoan parasites belonging to the genus Plasmodium.,These parasites infect not only humans but also other vertebrates, from reptiles and birds to mammals.,To date, over 200 species of Plasmodium have been formally described, and each species infects a certain range of hosts.,Plasmodium species that naturally infect humans and cause malaria in large areas of the world are limited to five-P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi.,The first four are specific for humans, while P. knowlesi is naturally maintained in macaque monkeys and causes zoonotic malaria widely in South East Asia.,Transmission of Plasmodium species between vertebrate hosts depends on an insect vector, which is usually the mosquito.,The vector is not just a carrier but the definitive host, where sexual reproduction of Plasmodium species occurs, and the parasite’s development in the insect is essential for transmission to the next vertebrate host.,The range of insect species that can support the critical development of Plasmodium depends on the individual parasite species, but all five Plasmodium species causing malaria in humans are transmitted exclusively by anopheline mosquitoes.,Plasmodium species have remarkable genetic flexibility which lets them adapt to alterations in the environment, giving them the potential to quickly develop resistance to therapeutics such as antimalarials and to change host specificity.,In this article, selected topics involving the Plasmodium species that cause malaria in humans are reviewed.

A distinctive feature of Plasmodium vivax infections is the overall low parasite density in peripheral blood.,Thus, identifying asymptomatic infected individuals in endemic communities requires diagnostic tests with high sensitivity.,The detection limits of molecular diagnostic tests are primarily defined by the volume of blood analysed and by the copy number of the amplified molecular marker serving as the template for amplification.,By using mitochondrial DNA as the multi-copy template, the detection limit can be improved more than tenfold, compared to standard 18S rRNA targets, thereby allowing detection of lower parasite densities.,In a very low transmission area in Brazil, application of a mitochondrial DNA-based assay increased prevalence from 4.9 to 6.5%.,The usefulness of molecular tests in malaria epidemiological studies is widely recognized, especially when precise prevalence rates are desired.,Of concern, however, is the challenge of demonstrating test accuracy and quality control for samples with very low parasite densities.,In this case, chance effects in template distribution around the detection limit constrain reproducibility.,Rigorous assessment of false positive and false negative test results is, therefore, required to prevent over- or under-estimation of parasite prevalence in epidemiological studies or when monitoring interventions.,The online version of this article (10.1186/s12936-018-2201-0) contains supplementary material, which is available to authorized users.

Annual mass drug administration with praziquantel has reduced schistosomiasis transmission in some highly endemic areas, but areas with persistent high endemicity have been identified across sub-Saharan Africa, including Uganda.,In these areas many children are rapidly reinfected post treatment, while some children remain uninfected or have low-intensity infections.,The aim of this mixed-methods study was to better understand variation in water contact locations, behaviours and infection risk in school-aged children within an area with persistent high endemicity to inform additional control efforts.,Data were collected in Bugoto, Mayuge District, Uganda.,Two risk groups were identified from a longitudinal cohort, and eight children with no/low-intensity infections and eight children with reinfections were recruited.,Individual structured day-long observations with a focus on water contact were conducted over two periods in 2018.,In all identified water contact sites, four snail surveys were conducted quarterly over 1 year.,All observed Biomphalaria snails were collected, counted and monitored in the laboratory for Schistosoma mansoni cercarial shedding for 3 weeks.,Children came into contact with water for a range of purposes, either directly at the water sources or by coming into contact with water collected previously.,Although some water contact practices were similar between the risk groups, only children with reinfection were observed fetching water for commercial purposes and swimming in water sources; this latter group of children also came into contact with water at a larger variety and number of sites compared to children with no/low-intensity infection.,Households with children with no/low-intensity infections collected rainwater more often.,Water contact was observed at 10 sites throughout the study, and a total of 9457 Biomphalaria snails were collected from these sites over four sampling periods.,Four lake sites had a significantly higher Biomphalaria choanomphala abundance, and reinfected children came into contact with water at these sites more often than children with no/low-intensity infections.,While only six snails shed cercariae, four were from sites only contacted by reinfected children.,Children with reinfection have more high-risk water contact behaviours and accessed water sites with higher B. choanomphala abundance, demonstrating that specific water contact behaviours interact with environmental features to explain variation in risk within areas with persistent high endemicity.,Targeted behaviour change, vector control and safe water supplies could reduce reinfection in school-aged children in these settings.,The online version contains supplementary material available at 10.1186/s13071-021-05121-6.

Evidence of an adverse influence of soil transmitted helminth (STH) infections on cognitive function and educational loss is equivocal.,Prior meta-analyses have focused on randomized controlled trials only and have not sufficiently explored the potential for disparate influence of STH infection by cognitive domain.,We re-examine the hypothesis that STH infection is associated with cognitive deficit and educational loss using data from all primary epidemiologic studies published between 1992 and 2016.,Medline, Biosis and Web of Science were searched for original studies published in the English language.,Cognitive function was defined in four domains (learning, memory, reaction time and innate intelligence) and educational loss in two domains (attendance and scholastic achievement).,Pooled effect across studies were calculated as standardized mean differences (SMD) to compare cognitive and educational measures for STH infected/non-dewormed children versus STH uninfected /dewormed children using Review Manager 5.3.,Sub-group analyses were implemented by study design, risk of bias (ROB) and co-prevalence of Schistosoma species infection.,Influential studies were excluded in sensitivity analysis to examine stability of pooled estimates.,We included 36 studies of 12,920 children.,STH infected/non-dewormed children had small to moderate deficits in three domains-learning, memory and intelligence (SMD: -0.44 to -0.27, P<0.01-0.03) compared to STH-uninfected/dewormed children.,There were no differences by infection/treatment status for reaction time, school attendance and scholastic achievement (SMD: -0.26 to -0.16, P = 0.06-0.19).,Heterogeneity of the pooled effects in all six domains was high (P<0.01; I2 = 66-99%).,Application of outlier treatment reduced heterogeneity in learning domain (P = 0.12; I2 = 33%) and strengthened STH-related associations in all domains but intelligence (SMD: -0.20, P = 0.09).,Results varied by study design and ROB.,Among experimental intervention studies, there was no association between STH treatment and educational loss/performance in tests of memory, reaction time and innate intelligence (SMD: -0.27 to 0.17, P = 0.18-0.69).,Infection-related deficits in learning persisted within design/ROB levels (SMD: -0.37 to -52, P<0.01) except for pre-vs post intervention design (n = 3 studies, SMD = -0.43, P = 0.47).,Deficits in memory, reaction time and innate intelligence persisted within observational studies (SMD: -0.23 to -0.38, all P<0.01) and high ROB strata (SMD:-0.37 to -0.83, P = 0.07 to <0.01).,Further, in Schistosoma infection co-prevalent settings, associations were generally stronger and statistically robust for STH-related deficits in learning, memory and reaction time tests(SMD:-0.36 to -0.55, P = 0.003-0.02).,STH-related deficits in school attendance and scholastic achievement was noted in low (SMD:-0.57, P = 0.05) and high ROB strata respectively.,We provide evidence of superior performance in five of six educational and cognitive domains assessed for STH uninfected/dewormed versus STH infected/not-dewormed school-aged children from helminth endemic regions.,Cautious interpretation is warranted due to high ROB in some of the primary literature and high between study variability in most domains.,Notwithstanding, this synthesis provides empirical support for a cognitive and educational benefit of deworming.,The benefit of deworming will be enhanced by strategically employing, integrated interventions.,Thus, multi-pronged inter-sectoral strategies that holistically address the environmental and structural roots of child cognitive impairment and educational loss in the developing world may be needed to fully realize the benefit of mass deworming programs.

Stopping interventions is a critical decision for parasite elimination programmes.,Quantifying the probability that elimination has occurred due to interventions can be facilitated by combining infection status information from parasitological surveys with extinction thresholds predicted by parasite transmission models.,Here we demonstrate how the integrated use of these two pieces of information derived from infection monitoring data can be used to develop an analytic framework for guiding the making of defensible decisions to stop interventions.,We present a computational tool to perform these probability calculations and demonstrate its practical utility for supporting intervention cessation decisions by applying the framework to infection data from programmes aiming to eliminate onchocerciasis and lymphatic filariasis in Uganda and Nigeria, respectively.,We highlight a possible method for validating the results in the field, and discuss further refinements and extensions required to deploy this predictive tool for guiding decision making by programme managers.,The decision when to stop an intervention is a critical component of parasite elimination programmes, but reliance on surveillance data alone can be inaccurate.,Here, Michael et al. combine parasite transmission model predictions with disease survey data to more reliably determine when interventions can be stopped.

The current WHO-led initiative to eradicate the macroparasitic disease, lymphatic filariasis (LF), based on single-dose annual mass drug administration (MDA) represents one of the largest health programs devised to reduce the burden of tropical diseases.,However, despite the advances made in instituting large-scale MDA programs in affected countries, a challenge to meeting the goal of global eradication is the heterogeneous transmission of LF across endemic regions, and the impact that such complexity may have on the effort required to interrupt transmission in all socioecological settings.,Here, we apply a Bayesian computer simulation procedure to fit transmission models of LF to field data assembled from 18 sites across the major LF endemic regions of Africa, Asia and Papua New Guinea, reflecting different ecological and vector characteristics, to investigate the impacts and implications of transmission heterogeneity and complexity on filarial infection dynamics, system robustness and control.,We find firstly that LF elimination thresholds varied significantly between the 18 study communities owing to site variations in transmission and initial ecological parameters.,We highlight how this variation in thresholds lead to the need for applying variable durations of interventions across endemic communities for achieving LF elimination; however, a major new result is the finding that filarial population responses to interventions ultimately reflect outcomes of interplays between dynamics and the biological architectures and processes that generate robustness/fragility trade-offs in parasite transmission.,Intervention simulations carried out in this study further show how understanding these factors is also key to the design of options that would effectively eliminate LF from all settings.,In this regard, we find how including vector control into MDA programs may not only offer a countermeasure that will reliably increase system fragility globally across all settings and hence provide a control option robust to differential locality-specific transmission dynamics, but by simultaneously reducing transmission regime variability also permit more reliable macroscopic predictions of intervention effects.,Our results imply that a new approach, combining adaptive modelling of parasite transmission with the use of biological robustness as a design principle, is required if we are to both enhance understanding of complex parasitic infections and delineate options to facilitate their elimination effectively.,The online version of this article (doi:10.1186/s12916-016-0557-y) contains supplementary material, which is available to authorized users.

A microscopy-based diagnosis is the gold standard for the detection and identification of malaria parasites in a patient’s blood.,However, the detection of cases involving a low number of parasites and the differentiation of species sometimes requires a skilled microscopist.,Although PCR-based diagnostic methods are already known to be very powerful tools, the time required to apply such methods is still much longer in comparison to traditional microscopic observation.,Thus, improvements to PCR systems are sought to facilitate the more rapid and accurate detection of human malaria parasites Plasmodium falciparum, P. vivax, P. ovale, and P. malariae, as well as P. knowlesi, which is a simian malaria parasite that is currently widely distributed in Southeast Asia.,A nested PCR that targets the small subunit ribosomal RNA genes of malaria parasites was performed using a “fast PCR enzyme”.,In the first PCR, universal primers for all parasite species were used.,In the second PCR, inner-specific primers, which targeted sequences from P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi, were used.,The PCR reaction time was reduced with the use of the “fast PCR enzyme”, with only 65 minutes required to perform the first and second PCRs.,The specific primers only reacted with the sequences of their targeted parasite species and never cross-reacted with sequences from other species under the defined PCR conditions.,The diagnoses of 36 clinical samples that were obtained using this new PCR system were highly consistent with the microscopic diagnoses.

This is the first case of Plasmodium knowlesi infection in a Japanese traveller returning from Malaysia.,In September 2012, a previously healthy 35-year-old Japanese man presented to National Center for Global Health and Medicine in Tokyo with a two-day history of daily fever, mild headaches and mild arthralgia.,Malaria parasites were found in the Giemsa-stained thin blood smear, which showed band forms similar to Plasmodium malariae.,Although a nested PCR showed the amplification of the primer of Plasmodium vivax and Plasmodium knowlesi, he was finally diagnosed with P. knowlesi mono-infection by DNA sequencing.,He was treated with mefloquine, and recovered without any complications.,DNA sequencing of the PCR products is indispensable to confirm P. knowlesi infection, however there is limited access to DNA sequencing procedures in endemic areas.,The extent of P. knowlesi transmission in Asia has not been clearly defined.,There is limited availability of diagnostic tests and routine surveillance system for reporting an accurate diagnosis in the Asian endemic regions.,Thus, reporting accurately diagnosed cases of P. knowlesi infection in travellers would be important for assessing the true nature of this emerging human infection.

Schistosoma constitutes a major public health problem and developmental challenges in the majority of developing and subtropical regions.,The World Health Organization has set guidelines for the control and elimination of schistosomiasis.,Ethiopia is providing school-based Mass Drug Administration (MDA) at the study areas of the Abbey and Didessa Valleys of western Ethiopian since 2015.,Moreover, mass treatment was already done in the same villages 30 years ago.,However, the current Schistosoma mansoni infection status among humans and snails in the study areas is not known.,Hence, the present study aims to determine the current status.,A community-based cross-sectional study was conducted in the three communities; Chessega, Agallu Metti and Shimala in Schistosoma mansoni endemic areas of the Abbey and Didessa valleys in Western Ethiopia.,Using the list of households obtained from the Kebele administration, a systematic sampling technique was used to select households in each village.,Even though the area is under the Ethiopian national Mass Drug Administration campaign, the present study reports prevalence above 50%.,Although the majority of the infections were moderate, we found that 13% had heavy infection, above 400 eggs per gram of stool, which is at the same level as before the treatment campaign 30 years ago.,The infection was significantly higher among those below 12 years of age, among non-attending school-age children and daily laborers.,Schistosoma mansoni infection is still a public health problem in the study areas, despite control efforts already 30 years ago and present mass treatment in the last years.,We suggest making the mass treatment campaign just early after the rainy season, when the snails are washed away.,This should be supplemented with provisions of clean water, sanitation, and hygiene (WASH) and reduction of water contact and possible snail control efforts’ to prevent reinfection.

There are health risks associated with wastewater and fecal sludge management and use, but little is known about the magnitude, particularly in rapidly growing urban settings of low- and middle-income countries.,We assessed the point-prevalence and risk factors of intestinal parasite infections in people with different exposures to wastewater and fecal sludge in Kampala, Uganda.,A cross-sectional survey was carried out in September and October 2013, enrolling 915 adults from five distinct population groups: workers maintaining wastewater facilities; workers managing fecal sludge; urban farmers; slum dwellers at risk of flooding; and slum dwellers without risk of flooding.,Stool samples were subjected to the Kato-Katz method and a formalin-ether concentration technique for the diagnosis of helminth and intestinal protozoa infections.,A questionnaire was administered to determine self-reported signs and symptoms, and risk factors for intestinal parasite infections.,Univariate and multivariate analyses, adjusted for sex, age, education, socioeconomic status, water, sanitation, and hygiene behaviors, were conducted to estimate the risk of infection with intestinal parasites and self-reported health outcomes, stratified by population group.,The highest point-prevalence of intestinal parasite infections was found in urban farmers (75.9%), whereas lowest point-prevalence was found in workers managing fecal sludge (35.8%).,Hookworm was the predominant helminth species (27.8%).,In urban farmers, the prevalence of Trichuris trichiura, Schistosoma mansoni, Ascaris lumbricoides, and Entamoeba histolytica/E. dispar was 15% and above.,For all investigated parasites, we found significantly higher odds of infection among urban farmers compared to the other groups (adjusted odds ratios ranging between 1.6 and 12.9).,In general, female participants had significantly lower odds of infection with soil-transmitted helminths and S. mansoni compared to males.,Higher educational attainment was negatively associated with the risk of intestinal protozoa infections, while socioeconomic status did not emerge as a significant risk factor for any tested health outcome.,Urban farmers are particularly vulnerable to infections with soil-transmitted helminths, S. mansoni, and intestinal protozoa.,Hence, our findings call for public health protection measures for urban farmers and marginalized communities, going hand-in-hand with integrated sanitation safety planning at city level.

As malaria endemic countries shift from control to elimination, the proportion of low density Plasmodium falciparum infections increases.,Current field diagnostic tools, such as microscopy and rapid diagnostic tests (RDT), with detection limits of approximately 100-200 parasites/µL (p/µL) and 800-1000 pg/mL histidine-rich protein 2 (HRP2), respectively, are unable to detect these infections.,A novel ultra-sensitive HRP2-based Alere™ Malaria Ag P.f RDT (uRDT) was evaluated in laboratory conditions to define the test’s performance against recombinant HRP2 and native cultured parasites.,The uRDT detected dilutions of P. falciparum recombinant GST-W2 and FliS-W2, as well as cultured W2 and ITG, diluted in whole blood down to 10-40 pg/mL HRP2, depending on the protein tested. uRDT specificity was 100% against 123 archived frozen whole blood samples.,Rapid test cross-reactivity with HRP3 was investigated using pfhrp2 gene deletion strains D10 and Dd2, pfhrp3 gene deletion strain HB3, and controls pfhrp2 and pfhrp3 double deletion strain 3BD5 and pfhrp2 and pfhrp3 competent strain ITG.,The commercial Standard Diagnostics, Inc.,BIOLINE Malaria Ag P.f RDT (SD-RDT) and uRDT detected pfhrp2 positive strains down to 49 and 3.13 p/µL, respectively.,The pfhrp2 deletion strains were detected down to 98 p/µL by both tests.,The performance of the uRDT was variable depending on the protein, but overall showed a greater than 10-fold improvement over the SD-RDT.,The uRDT also exhibited excellent specificity and showed the same cross-reactivity with HRP3 as the SD-RDT.,Together, the results support the uRDT as a more sensitive HRP2 test that could be a potentially effective tool in elimination campaigns.,Further clinical evaluations for this purpose are merited.

A pivotal phase III study of the RTS,S/AS01 malaria candidate vaccine is ongoing in several research centres across Africa.,The development and establishment of quality systems was a requirement for trial conduct to meet international regulatory standards, as well as providing an important capacity strengthening opportunity for study centres.,Standardized laboratory methods and quality assurance processes were implemented at each of the study centres, facilitated by funding partners.,A robust protocol for determination of parasite density based on actual blood cell counts was set up in accordance with World Health Organization recommendations.,Automated equipment including haematology and biochemistry analyzers were put in place with standard methods for bedside testing of glycaemia, base excess and lactacidaemia.,Facilities for X-rays and basic microbiology testing were also provided or upgraded alongside health care infrastructure in some centres.,External quality assurance assessment of all major laboratory methods was established and method qualification by each laboratory demonstrated.,The resulting capacity strengthening has ensured laboratory evaluations are conducted locally to the high standards required in clinical trials.,Major efforts by study centres, together with support from collaborating parties, have allowed standardized methods and robust quality assurance processes to be put in place for the phase III evaluation of the RTS, S/AS01 malaria candidate vaccine.,Extensive training programmes, coupled with continuous commitment from research centre staff, have been the key elements behind the successful implementation of quality processes.,It is expected these activities will culminate in healthcare benefits for the subjects and communities participating in these trials.,Clinicaltrials.gov NCT00866619

Malaria has steadily increased in the Peruvian Amazon over the last five years.,This study aimed to determine the parasite prevalence and micro-geographical heterogeneity of Plasmodium vivax parasitaemia in communities of the Peruvian Amazon.,Four cross-sectional active case detection surveys were conducted between May and July 2015 in four riverine communities in Mazan district.,Analysis of 2785 samples of 820 individuals nested within 154 households for Plasmodium parasitaemia was carried out using light microscopy and qPCR.,The spatio-temporal distribution of Plasmodium parasitaemia, dominated by P. vivax, was shown to cluster at both household and community levels.,Of enrolled individuals, 47% had at least one P. vivax parasitaemia and 10% P. falciparum, by qPCR, both of which were predominantly sub-microscopic and asymptomatic.,Spatial analysis detected significant clustering in three communities.,Our findings showed that communities at small-to-moderate spatial scales differed in P. vivax parasite prevalence, and multilevel Poisson regression models showed that such differences were influenced by factors such as age, education, and location of households within high-risk clusters, as well as factors linked to a local micro-geographic context, such as travel and occupation.,Complex transmission patterns were found to be related to human mobility among communities in the same micro-basin.

Plasmodium vivax preferentially infects Duffy-positive reticulocytes and infections typically have few parasite-infected cells in the peripheral circulation.,These features complicate detection and quantification by flow cytometry (FC) using standard nucleic acid-based staining methods.,A simple antibody-based FC method was developed for rapid parasite detection along with simultaneous detection of other parasite and erythrocyte markers.,Clinical samples were collected from patients diagnosed with P. vivax at a district Malaria Clinic in Kanchanaburi, Thailand.,One μL of infected blood was washed, fixed, stained with a Plasmodium pan-specific anti-PfBiP antibody conjugated with Alexa Fluor 660, and analysed by FC.,Additional primary conjugated antibodies for stage-specific markers of P. vivax for late trophozoite-early schizonts (MSP1-Alexa Fluor 660), late-stage schizonts (DBP-Alexa Fluor 555), and sexual stages (Pvs16) were used to differentiate intra-erythrocytic developmental stages.,The percentages of P. vivax-infected cells determined by the FC method and manually by microscopic examination of Giemsa-stained thick blood smears were positively correlated by Spearman’s rank correlation coefficient (R2 = 0.93843) from 0.001 to 1.00% P. vivax-infected reticulocytes.,The FC-based method is a simple, robust, and efficient method for detecting P. vivax-infected reticulocytes.

In clinical trials of therapy for uncomplicated Plasmodium falciparum, there are usually some patients who fail treatment even in the absence of drug resistance.,Treatment failures, which can be due to recrudescence or re-infection, are categorized as ‘clinical’ or ‘parasitological’ failures, the former indicating that symptoms have returned.,Asymptomatic recrudescence has public health implications for continued malaria transmission and may be important for the spread of drug-resistant malaria.,As the number of recrudescences in an individual trial is often low, it is difficult to assess how commonplace asymptomatic recrudescence is, and with what factors it is associated.,A systematic literature review was carried out on clinical trials of artemether-lumefantrine (AL) in patients seeking treatment for symptomatic uncomplicated falciparum malaria, and information on symptoms during treatment failure was recorded.,Only treatment failures examined by polymerase chain reaction (PCR) were included, so as to exclude re-infections.,A multivariable Bayesian regression model was used to explore factors potentially explaining the proportion of recrudescent infections which are symptomatic across the trials included in the study.,Across 60 published trials, including 9137 malaria patients, 37.8% [95% CIs (26.6-49.4%)] of recrudescences were symptomatic.,A positive association was found between transmission intensity and the observed proportion of recrudescences that were asymptomatic.,Symptoms were more likely to return in trials that only enrolled children aged < 72 months [odds ratio = 1.62, 95% CIs (1.01, 2.59)].,However, 84 studies had to be excluded from this analysis, as recrudescences were not specified as symptomatic or asymptomatic.,AL, the most widely used treatment for uncomplicated P. falciparum in Africa, remains a highly efficacious drug in most endemic countries.,However in the small proportion of patients where AL does not clear parasitaemia, the majority of patients do not develop symptoms again and thus would be unlikely to seek another course of treatment.,This continued asymptomatic parasite carriage in patients who have been treated may have implications for drug-resistant parasites being introduced into high-transmissions settings.

Recent anti-malarial resistance monitoring in Angola has shown efficacy of artemether-lumefantrine (AL) in certain sites approaching the key 90% lower limit of efficacy recommended for artemisinin-based combination therapy.,In addition, a controversial case of malaria unresponsive to artemisinins was reported in a patient infected in Lunda Sul Province in 2013.,During January-June 2015, investigators monitored the clinical and parasitological response of children with uncomplicated Plasmodium falciparum infection treated with AL, artesunate-amodiaquine (ASAQ), or dihydroartemisinin-piperaquine (DP).,The study comprised two treatment arms in each of three provinces: Benguela (AL, ASAQ), Zaire (AL, DP), and Lunda Sul (ASAQ, DP).,Samples from treatment failures were analysed for molecular markers of resistance for artemisinin (K13) and lumefantrine (pfmdr1).,A total of 467 children reached a study endpoint.,Fifty-four treatment failures were observed: four early treatment failures, 40 re-infections and ten recrudescences.,Excluding re-infections, the 28-day microsatellite-corrected efficacy was 96.3% (95% CI 91-100) for AL in Benguela, 99.9% (95-100) for ASAQ in Benguela, 88.1% (81-95) for AL in Zaire, and 100% for ASAQ in Lunda Sul.,For DP, the 42-day corrected efficacy was 98.8% (96-100) in Zaire and 100% in Lunda Sul.,All treatment failures were wild type for K13, but all AL treatment failures had pfmdr1 haplotypes associated with decreased lumefantrine susceptibility.,No evidence was found to corroborate the specific allegation of artemisinin resistance in Lunda Sul.,The efficacy below 90% of AL in Zaire matches findings from 2013 from the same site.,Further monitoring, particularly including measurement of lumefantrine blood levels, is recommended.,The online version of this article (doi:10.1186/s12936-017-1712-4) contains supplementary material, which is available to authorized users.

Despite the enormous morbidity attributed to schistosomiasis, there is still no vaccine to combat the disease for the hundreds of millions of infected people.,The anthelmintic drug, praziquantel, is the mainstay treatment option, although its molecular mechanism of action remains poorly defined.,Praziquantel treatment damages the outermost surface of the parasite, the tegument, liberating surface antigens from dying worms that invoke a robust immune response which in some subjects results in immunologic resistance to reinfection.,Herein we term this phenomenon Drug-Induced Vaccination (DIV).,To identify the antigenic targets of DIV antibodies in urogenital schistosomiasis, we constructed a recombinant proteome array consisting of approximately 1,000 proteins informed by various secretome datasets including validated proteomes and bioinformatic predictions.,Arrays were screened with sera from human subjects treated with praziquantel and shown 18 months later to be either reinfected (chronically infected subjects, CI) or resistant to reinfection (DIV).,IgG responses to numerous antigens were significantly elevated in DIV compared to CI subjects, and indeed IgG responses to some antigens were completely undetectable in CI subjects but robustly recognized by DIV subjects.,One antigen in particular, a cystatin cysteine protease inhibitor stood out as a unique target of DIV IgG, so recombinant cystatin was produced, and its vaccine efficacy assessed in a heterologous Schistosoma mansoni mouse challenge model.,While there was no significant impact of vaccination with adjuvanted cystatin on adult worm numbers, highly significant reductions in liver egg burdens (45-55%, P<0.0001) and intestinal egg burdens (50-54%, P<0.0003) were achieved in mice vaccinated with cystatin in two independent trials.,This study has revealed numerous antigens that are targets of DIV antibodies in urogenital schistosomiasis and offer promise as subunit vaccine targets for a drug-linked vaccination approach to controlling schistosomiasis.

With the vision of "a world free of schistosomiasis", the World Health Organization (WHO) has set ambitious goals, by 2020 and 2025, for, respectively, the control and elimination as a public health problem (EPHP) of this debilitating disease.,As these milestones become imminent and if programmes are to succeed, it is crucial to gather quantitative evidence to support the existing universal approach of WHO programmatic guidelines.,Multi-year cross-sectional data were collated and analysed from nine national schistosomiasis control programmes - eight in sub-Saharan Africa, and Yemen.,Data were analysed by Schistosoma species (Schistosoma mansoni, S. haematobium), number of treatment rounds, overall prevalence and prevalence of heavy-intensity infection.,All but one country programme achieved control of morbidity targets for both schistosome species considerably sooner than current WHO guidelines project.,Programmes with low baseline endemicity levels were more likely to reach control and EPHP targets.,Intra-country variation was seen in the relationship between overall prevalence and that of heavy-intensity infection, and between treatment rounds, highlighting the challenges of using one metric to define control in all epidemiological settings.,If countries follow the current guidelines, many programmes would need to continue beyond 2020.,Our results suggest the need of a reduced timeframe from baseline to the next programmatic decision point (i.e. <5 years, rather than the proposed 5-10 years).,This has important implications for national programmes, determining impact and resource allocations as well as indicating when to re-assess to determine the next treatment strategy.

Trypanosoma brucei is an extracellular parasite that causes sleeping sickness.,In mammalian hosts, trypanosomes are thought to exist in two major niches: early in infection, they populate the blood; later, they breach the blood-brain barrier.,Working with a well-established mouse model, we discovered that adipose tissue constitutes a third major reservoir for T. brucei.,Parasites from adipose tissue, here termed adipose tissue forms (ATFs), can replicate and were capable of infecting a naive animal.,ATFs were transcriptionally distinct from bloodstream forms, and the genes upregulated included putative fatty acid β-oxidation enzymes.,Consistent with this, ATFs were able to utilize exogenous myristate and form β-oxidation intermediates, suggesting that ATF parasites can use fatty acids as an external carbon source.,These findings identify the adipose tissue as a niche for T. brucei during its mammalian life cycle and could potentially explain the weight loss associated with sleeping sickness.,•T. brucei parasites accumulate in the adipose tissue early after mouse infection•Adipose tissue forms (ATFs) can replicate and are capable of infecting naive mice•ATFs are transcriptionally distinct and upregulate genes for fatty acid metabolism•ATFs can actively uptake exogenous myristate and form β-oxidation intermediates,T. brucei parasites accumulate in the adipose tissue early after mouse infection,Adipose tissue forms (ATFs) can replicate and are capable of infecting naive mice,ATFs are transcriptionally distinct and upregulate genes for fatty acid metabolism,ATFs can actively uptake exogenous myristate and form β-oxidation intermediates,Trypanosoma brucei is found in the bloodstream and interstitial compartment of several organs in the mammalian host.,Trindade et al. uncover the adipose tissue as a major extravascular parasite niche.,Extensive remodeling of parasite gene expression in this lipid-rich environment includes upregulation of fatty acid β-oxidation enzymes, suggestive of a functional adaptation.

•Much of what we know about trypanosomatid biology has its origin in studies on VSGs.,•Monotelomeric VSG expression and epigenetic switching are remarkable examples of allelic exclusion.,•DNA repair processes allow a new VSG to be copied into the single transcribed locus.,Much of what we know about trypanosomatid biology has its origin in studies on VSGs.,Monotelomeric VSG expression and epigenetic switching are remarkable examples of allelic exclusion.,DNA repair processes allow a new VSG to be copied into the single transcribed locus.,Studies on Variant Surface Glycoproteins (VSGs) and antigenic variation in the African trypanosome, Trypanosoma brucei, have yielded a remarkable range of novel and important insights.,The features first identified in T. brucei extend from unique to conserved-among-trypanosomatids to conserved-among-eukaryotes.,Consequently, much of what we now know about trypanosomatid biology and much of the technology available has its origin in studies related to VSGs.,T. brucei is now probably the most advanced early branched eukaryote in terms of experimental tractability and can be approached as a pathogen, as a model for studies on fundamental processes, as a model for studies on eukaryotic evolution or often all of the above.,In terms of antigenic variation itself, substantial progress has been made in understanding the expression and switching of the VSG coat, while outstanding questions continue to stimulate innovative new approaches.,There are large numbers of VSG genes in the genome but only one is expressed at a time, always immediately adjacent to a telomere.,DNA repair processes allow a new VSG to be copied into the single transcribed locus.,A coordinated transcriptional switch can also allow a new VSG gene to be activated without any detectable change in the DNA sequence, thereby maintaining singular expression, also known as allelic exclusion.,I review the story behind VSGs; the genes, their expression and switching, their central role in T. brucei virulence, the discoveries that emerged along the way and the persistent questions relating to allelic exclusion in particular.

Guinea reported its first case of COVID-19 on March 12, 2020.,Soon thereafter, a national state of emergency was declared, all land borders were closed, schools were shut down, and public gatherings were limited.,Many health activities, including field-based activities targeting neglected tropical diseases (NTDs), were paused.,The World Health Organization (WHO) issued updated guidance on the resumption of NTD field-based activities on July 27, 2020.,In response, the Guinea Ministry of Health (MoH) and its partners planned and resumed mass drug administration (MDA) in mid-August to September 2020 in 19 health districts.,A risk-benefit assessment was conducted to identify potential risks associated with the MDA in the COVID-19 context.,Following this assessment, a risk mitigation plan with barrier measures was developed to guide MDA implementation.,These measures included COVID-19 testing for all national staff leaving Conakry, mask wearing, social distancing of two meters, and hand washing/sanitizing.,A checklist was developed and used to monitor compliance to risk mitigation measures.,Data on adherence to risk mitigation measures were collected electronically during the MDA.,A total of 120 checklists, representing 120 community drug distributor (CDD) teams (two CDDs per team) and 120 households, were completed.,Results indicated that washing or disinfecting hands was practiced by 68.3% of CDD teams, compared to 45.0% among households.,Face masks to cover the mouth and nose were worn by 79.2% of CDD teams, while this was low among households (23.3%).,In 87.5% of households, participants did not touch the dose pole and in 88.3% of CDD teams, CDDs did not touch the hands of the participants while giving the drugs.,A large majority of CDD teams (94.2%) and household members (94.2%) were willing to participate in the MDA despite the pandemic.,The epidemiological coverage was ≥65% for lymphatic filariasis, onchocerciasis and soil-transmitted helminths in 10 out of 19 HDs and ≥75% for schistosomiasis for school-aged children in 7 out of 11 HDs.,Guinea was one of the first countries in Africa to resume MDA activities during the COVID-19 pandemic without causing an observed increase of transmission.,The development of a risk mitigation plan and a method to monitor adherence to barrier measures was critical to this unprecedented effort.,The rapid incorporation of COVID-19 barrier measures and their acceptance by CDDs and household members demonstrated both the adaptability of the National NTD Program to respond to emerging issues and the commitment of the MoH to implement NTD programs.

Since the turn of the century, the global community has made great progress towards the elimination of gambiense human African trypanosomiasis (HAT).,Elimination programs, primarily relying on screening and treatment campaigns, have also created a rich database of HAT epidemiology.,Mathematical models calibrated with these data can help to fill remaining gaps in our understanding of HAT transmission dynamics, including key operational research questions such as whether integrating vector control with current intervention strategies is needed to achieve HAT elimination.,Here we explore, via an ensemble of models and simulation studies, how including or not disease stage data, or using more updated data sets affect model predictions of future control strategies.

Repeat national household surveys suggest highly variable malaria transmission and increasing coverage of high-impact malaria interventions throughout Zambia.,Many areas of very low malaria transmission, especially across southern and central regions, are driving efforts towards sub-national elimination.,Reactive case detection (RCD) is conducted in Southern Province and urban areas of Lusaka in connection with confirmed incident malaria cases presenting to a community health worker (CHW) or clinic and suspected of being the result of local transmission.,CHWs travel to the household of the incident malaria case and screen individuals living in adjacent houses in urban Lusaka and within 140 m in Southern Province for malaria infection using a rapid diagnostic test, treating those testing positive with artemether-lumefantrine.,Reactive case detection improves access to health care and increases the capacity for the health system to identify malaria infections.,The system is useful for targeting malaria interventions, and was instrumental for guiding focal indoor residual spraying in Lusaka during the 2014/2015 spray season.,Variations to maximize impact of the current RCD protocol are being considered, including the use of anti-malarials with a longer lasting, post-treatment prophylaxis.,The RCD system in Zambia is one example of a malaria elimination surveillance system which has increased access to health care within rural communities while leveraging community members to build malaria surveillance capacity.

In malaria-endemic countries, large proportions of infected individuals are asymptomatic, constituting a reservoir of parasites for infection of newly hatched mosquitoes.,This study evaluated the impact of screening and treatment of asymptomatic carriers of Plasmodium falciparum.,Eighteen villages were randomized (1:1) to study arms and inhabitants participated in four community screening campaigns: three before the rainy season ~1 month apart, and the fourth after the rains at ~12 months.,On day 1 of campaigns 1-3, asymptomatic carriers in the intervention arm were identified by rapid diagnostic test and treated with artemether-lumefantrine.,Outcomes were symptomatic malaria with parasite density >5,000/μL per person-year in children < 5 years and change in haemoglobin between days 1 and 28 of campaign 1.,At 12 months, the number of symptomatic malaria episodes with a parasite density >5,000/μL per person-year in children < 5 years was not significantly different between arms (1.69 vs 1.60, p = 0.3482).,Mean haemoglobin change in asymptomatic carriers during campaign 1 was greater in the intervention vs control arm (+0.53 g/dL vs -0.21 g/dL, p < 0.0001).,ANCOVA demonstrated that mean asymptomatic carriage at the cluster level was lower in the intervention vs control arm at day 1 of campaigns 2 (5.0% vs 34.9%, p < 0.0001) and 3 (3.5% vs 31.5%, p < 0.0001), but showed only a small difference at day 1 of campaign 4 (34.6% vs 37.6%, p = 0.2982).,Mean gametocyte carriage was lower in the intervention vs control arm at day 1 of campaigns 2 and 3 (0.7% vs 5.4%, p < 0.0001; 0.5% vs 5.8%, p < 0.0001), but was similar at day 1 of campaign 4 (4.9% vs 5.1%, p = 0.7208).,Systematic screening and treatment of asymptomatic carriers at the community level did not reduce clinical malaria incidence in the subsequent transmission season, indicating greater levels of parasite clearance are required to achieve a sustained impact in this setting.

Insecticide resistance threatens effective vector control, especially for mosquitoes and malaria.,To manage resistance, recommended insecticide use strategies include mixtures, sequences and rotations.,New insecticides are being developed and there is an opportunity to develop use strategies that limit the evolution of further resistance in the short term.,A 2013 review of modelling and empirical studies of resistance points to the advantages of mixtures.,However, there is limited recent, accessible modelling work addressing the evolution of resistance under different operational strategies.,There is an opportunity to improve the level of mechanistic understanding within the operational community of how insecticide resistance can be expected to evolve in response to different strategies.,This paper provides a concise, accessible description of a flexible model of the evolution of insecticide resistance.,The model is used to develop a mechanistic picture of the evolution of insecticide resistance and how it is likely to respond to potential insecticide use strategies.,The aim is to reach an audience unlikely to read a more detailed modelling paper.,The model itself, as described here, represents two independent genes coding for resistance to two insecticides.,This allows the representation of the use of insecticides in isolation, sequence and mixtures.,The model is used to demonstrate the evolution of resistance under different scenarios and how this fits with intuitive reasoning about selection pressure.,Using an insecticide in a mixture, relative to alone, always prompts slower evolution of resistance to that insecticide.,However, when resistance to both insecticides is considered, resistance thresholds may be reached later for a sequence relative to a mixture.,Increasing the ability of insecticides to kill susceptible mosquitoes (effectiveness), has the most influence on favouring a mixture over a sequence because one highly effective insecticide provides more protection to another in a mixture.,The model offers an accessible description of the process of insecticide resistance evolution and how it is likely to respond to insecticide use.,A simple online user-interface allowing further exploration is also provided.,These tools can contribute to an improved discussion about operational decisions in insecticide resistance management.

This article reports the changing pattern of US President’s Malaria Initiative-funded IRS in sub-Saharan Africa between 2008 and 2015.,IRS coverage in sub-Saharan Africa increased from <2 % of the at-risk population in 2005, to 11 % or 78 million people in 2010, mainly as a result of increased funding from PMI.,The scaling up of IRS coverage in sub-Saharan Africa has been successful in several epidemiological settings and contributed to reduced malaria transmission rates.,However, the spread and intensification of pyrethroid resistance in malaria vectors led many control programmes to spray alternative insecticides.,Between 2009 and 2013, pyrethroid spraying decreased from 87 % (13/15) of PMI-funded countries conducting IRS to 44 % (7/16), while bendiocarb use increased from 7 % (1/15) to 56 % (9/16).,Long-lasting pirimiphos-methyl CS received WHOPES recommendation in 2013 and was scheduled to be sprayed in 85 % (11/13) of PMI-funded countries conducting IRS in 2015.,The gradual replacement of relatively inexpensive pyrethroids, firstly with bendiocarb (carbamate) and subsequently with pirimiphos methyl CS (organophosphate), has contributed to the downscaling of most PMI-funded IRS programmes.,Overall, there was a 53 % decrease in the number of structures sprayed between years of peak coverage and 2015, down from 9.04 million to 4.26 million structures.,Sizeable reductions in the number of structures sprayed were reported in Madagascar (56 %, 576,320-254,986), Senegal (64 %, 306,916-111,201), Tanzania (68 %, 1,224,095-389,714) and Zambia (63 %, 1,300,000-482,077), while in Angola, Liberia and Malawi PMI-funded spraying was suspended.,The most commonly cited reason was increased cost of pesticides, as vector resistance necessitated switching from pyrethroids to organophosphates.,There are worrying preliminary reports of malaria resurgence following IRS withdrawal in parts of Benin, Tanzania and Uganda.,The increase in malaria cases following the end of the Global Malaria Eradication Programme in 1969 highlights the fragility of such gains when control efforts are weakened.,At present there are several countries reliant on organophosphates and carbamates for IRS, and increasing incipient resistance is a serious threat that could result in IRS no longer being viable.,A portfolio of new cost-effective insecticides with different modes of action is urgently needed.

Soil-transmitted helminths (STHs) comprise a group of helminth parasites that are included in the list of Neglected Tropical Diseases and require a passage through the soil to become infective.,Several studies have detected that infection with STHs are associated with certain socioeconomic, environmental and soil characteristics.,In Argentina, the presence of these parasites has been detected through a few point studies conducted in localities from 11 of the 23 provinces that comprise the country.,The most important characteristics previously associated with the presence of STHs were identified and ranked through the use of an expert survey and the Analytical Hierarchy Process (AHP) in order to construct a risk map of STHs specific for Argentina.,Prevalence data from previous studies was used to validate the generated risk map.,The map shows that half of Argentina, from the Central provinces to the North, contains localities with the characteristics necessary for the development of these parasites.,The predicted map should serve as a useful tool for guiding the identification of survey areas for the generation of baseline data, detecting hotspots of infection, planning and prioritizing areas for control interventions, and eventually performing post-implementation surveillance activities.

Current data on soil-transmitted helminth infections, anemia and malnutrition that are largely neglected is vital to the control and management of them in a specific setting.,This study was, therefore, aimed at determining the status of the three health concerns in one of the high-risk groups, schoolchildren, in South Ethiopia.,Among the 443 sampled schoolchildren, 54% were infected with soil-transmitted helminths (STHs) and 15.4% of them had anaemia, while the prevalence rate of undernutrition was 28.9%.,Species-wise, prevalence of STH infections was 21.7, 16.7, 7.2 and 8.4% for Ascaris lumbricoides, the hookworms, Trichuris trichiura and mixed infections, respectively.,Untreated drinking water, high frequency of sucking fingernails and open defecation were significantly associated with risk of getting STH infections.,Child positivity for STH infection didn’t show any significant association with undernutrition of the children.,Anaemia was significantly correlated with hookworm (adjusted odds ratio (AOR) = 2.96, 95% confidence interval (CI) = 2.15, 4.86), A. lumbricoides (AOR = 1.93, 95% CI = 1.13, 3.01) and polyparasitism (AOR = 1.54, 95% CI = 1.04, 2.64).,In addition, children with heavy intensities of hookworm infections and those undernourished were more likely to suffer from anaemia with P = 0.001 and P = 0.007, respectively.

Methodological applications of the high sensitivity genus-specific Schistosoma CAA strip test, allowing detection of single worm active infections (ultimate sensitivity), are discussed for efficient utilization in sample pooling strategies.,Besides relevant cost reduction, pooling of samples rather than individual testing can provide valuable data for large scale mapping, surveillance, and monitoring.,The laboratory-based CAA strip test utilizes luminescent quantitative up-converting phosphor (UCP) reporter particles and a rapid user-friendly lateral flow (LF) assay format.,The test includes a sample preparation step that permits virtually unlimited sample concentration with urine, reaching ultimate sensitivity (single worm detection) at 100% specificity.,This facilitates testing large urine pools from many individuals with minimal loss of sensitivity and specificity.,The test determines the average CAA level of the individuals in the pool thus indicating overall worm burden and prevalence.,When requiring test results at the individual level, smaller pools need to be analysed with the pool-size based on expected prevalence or when unknown, on the average CAA level of a larger group; CAA negative pools do not require individual test results and thus reduce the number of tests.,Straightforward pooling strategies indicate that at sub-population level the CAA strip test is an efficient assay for general mapping, identification of hotspots, determination of stratified infection levels, and accurate monitoring of mass drug administrations (MDA).,At the individual level, the number of tests can be reduced i.e. in low endemic settings as the pool size can be increased as opposed to prevalence decrease.,At the sub-population level, average CAA concentrations determined in urine pools can be an appropriate measure indicating worm burden.,Pooling strategies allowing this type of large scale testing are feasible with the various CAA strip test formats and do not affect sensitivity and specificity.,It allows cost efficient stratified testing and monitoring of worm burden at the sub-population level, ideally for large-scale surveillance generating hard data for performance of MDA programs and strategic planning when moving towards transmission-stop and elimination.

Mapping and diagnosis of infections by the three major schistosome species (Schistosoma haematobium, S. mansoni and S. japonicum) has been done with assays that are known to be specific but increasingly insensitive as prevalence declines or in areas with already low prevalence of infection.,This becomes a true challenge to achieving the goal of elimination of schistosomiasis because the multiplicative portion of the life-cycle of schistosomes, in the snail vector, favors continued transmission as long as even a few people maintain low numbers of worms that pass eggs in their excreta.,New mapping tools based on detection of worm antigens (circulating cathodic antigen - CCA; circulating anodic antigen - CAA) in urine of those infected are highly sensitive and the CAA assay is reported to be highly specific.,Using these tools in areas of low prevalence of all three of these species of schistosomes has demonstrated that more people harbor adult worms than are regularly excreting eggs at a level detectable by the usual stool assay (Kato-Katz) or by urine filtration.,In very low prevalence areas this is sometimes 6- to10-fold more.,Faced with what appears to be a sizable population of “egg-negative/worm-positive schistosomiasis” especially in areas of very low prevalence, national NTD programs are confounded about what guidelines and strategies they should enact if they are to proceed toward a goal of elimination.,There is a critical need for continued evaluation of the assays involved and to understand the contribution of this “egg-negative/worm-positive schistosomiasis” condition to both individual morbidity and community transmission.,There is also a critical need for new guidelines based on the use of these more sensitive assays for those national NTD programs that wish to move forward to strategies designed for elimination.,The online version of this article (doi:10.1186/s40249-017-0275-5) contains supplementary material, which is available to authorized users.

The growing threat of insecticide resistance in mosquitoes and drug resistance in the Plasmodium parasites increases the importance of ensuring appropriate malaria case management and enabling positive health-seeking behaviour.,Treatment-seeking behaviours are poorly characterized in malaria-endemic regions that have been the focus of intensive control and elimination campaigns.,This study uses a comprehensive approach to shed light on the determinants of malaria treatment-seeking behaviours from different perspectives.,The authors conducted cross-sectional surveys from 832 households, fifteen health centers, and 135 retailers across three sites in the Emuhaya and Kakamega districts of the western Kenyan highlands.,Participants were recruited via random sampling and data were collected with the use of a structured questionnaire about malaria treatment-seeking behaviour.,All households, healthcare facilities, and retailers were mapped using a handheld GPS and a GIS algorithm was used to calculate “walk distance” based on the Tobler rule; an estimate of this distance was used to calculate the travel time used in the analyses.,Across the three sites, 47.5-78.9 % of the residents sought diagnosis and treatment at hospitals, clinics, or dispensaries; 6.3-26.1 % of the residents sought malaria care only at pharmaceutical retailers.,Overall, 40.3-59.4 % of residents reported delaying seeking care for more than 24 h after fever onset.,After adjustment, residents who chose to visit a pharmaceutical retail facility rather than a hospital were 121 and 307 % more likely to delay seeking medical care after fever onset than those who reported choosing a healthcare facility for treatment.,No significant association was found between travel time and delay in seeking care.,The surveys of the healthcare facilities indicated an average total cost per patient per visit was 112 KES ($1.40 US) for public facilities and 165 KES ($2.06 US) for private facilities.,Understanding the local health behaviours that perpetuate transmission of malaria will help develop targeted preventive measures and educational interventions that can empower the residents with the knowledge needed to combat malaria in a safe and effective manner.,Ensuring patient access to health care facilities in countries with high disease burdens has broader implications on measures of equity and on public health prevention methodologies.,The online version of this article (doi:10.1186/s12936-016-1232-7) contains supplementary material, which is available to authorized users.

Controversy surrounds the precise numbers of malaria deaths and clinical episodes in Africa.,This would not have surprised malariologists working in Africa 60 years ago as they began to unravel the enigma that is ‘malaria’.,Malaria is a complex disease manifesting as a multitude of symptoms, degrees of severity and indirect morbid consequences.,Clinical immunity develops quickly and the presence of infection cannot always be used to distinguish between malaria and other illnesses.,During the 1950s and 1960s parasite prevalence was used in preference to statistics on malaria mortality and morbidity.,An argument is made for a resurrection of this measure of the quantity of malaria across Africa as a more reliable means to understand the impact of control.

Toxoplasmosis, a neglected tropical disease caused by the protozoan parasite Toxoplasma gondii, occurs throughout the world.,Human T. gondii infection is asymptomatic in 80% of the population; however, the infection is life-threatening and causes substantial neurologic damage in immunocompromised patients such as HIV-infected persons.,The major purpose of this study was to investigate the seroprevalence of T. gondii infection in subjects infected with HIV/AIDS in eastern China.,Our findings showed 9.7% prevalence of anti-T. gondii IgG antibody in HIV/AIDS patients, which was higher than in intravenous drug users (2.2%) and healthy controls (4.7%), while no significant difference was observed in the seroprevalence of anti-Toxoplasma IgM antibody among all participants (P>0.05).,Among all HIV/AIDS patients, 15 men (7.7%) and 10 women (15.9%) were positive for anti-T. gondii IgG antibody; however, no significant difference was detected in the seroprevalence of anti-Toxoplasma IgG antibody between males and females.,The frequency of anti-Toxoplasma IgG antibody was 8.0%, 13.2%, 5.5%, and 0% in patients with normal immune function (CD4+ T-lymphocyte count ≥500 cells/ml), immunocompromised patients (cell count ≥200 and <500 cells/ml), severely immunocompromised patients (cell count ≥50 and <200 cells/ml), and advanced AIDS patients, respectively (cell count <50 cells/ml), while only 3 immunocompromised patients were positive for anti-T. gondii IgM antibody.,The results indicate a high seroprevalence of T. gondii infection in HIV/AIDS patients in eastern China, and a preventive therapy for toxoplasmosis may be given to HIV/AIDS patients based on CD4+ T lymphocyte count.

Seroepidemiological status of toxoplasmosis among the residents of Jeju island was surveyed and evaluated by ELISA with crude extract of Toxoplasma gondii.,The sera of 2,348 residents (male 1,157 and female 1,191) were collected and checked for the IgG antibody titers, which showed 13.2% positive rate (309 sera).,The positive rates were increasing gradually according to the age from 4.3% in teenage to 20.6% in seventies.,The positive rates were significantly different between the sex by 16.2% for male and 10.2% for female (P<0.05).,This positive rate of toxoplasmosis in Jeju island residents is regarded relatively higher than any other regions of Korea.,And the high positive rate may be maintained continuously among Jeju island residents without any clear reasons until now but due to some parts peculiar socio-cultural tradition of Jeju island.,Therefore, it is necessary to study further the epidemiology of toxoplasmosis of Jeju island.

In a markedly seasonal malaria setting, the transition from the transmission-free dry season to the transmission season depends on the resurgence of the mosquito population following the start of annual rains.,The sudden onset of malaria outbreaks at the start of the transmission season suggests that parasites persist during the dry season and respond to either the reappearance of vectors, or correlated events, by increasing the production of transmission stages.,Here, we investigate whether Plasmodium falciparum gametocyte density and the correlation between gametocyte density and parasite density show seasonal variation in chronic (largely asymptomatic) carriers in eastern Sudan.,We recruited and treated 123 malaria patients in the transmission season 2001.,We then followed them monthly during four distinct consecutive epidemiological seasons: transmission season 1, transmission-free season, pre-clinical period, and transmission season 2.,In samples collected from 25 participants who fulfilled the selection criteria of the current analysis, we used quantitative PCR (qPCR) and RT-qPCR to quantify parasite and gametocyte densities, respectively.,We observed a significant increase in gametocyte density and a significantly steeper positive correlation between gametocyte density and total parasite density during the pre-clinical period compared to the preceding transmission-free season.,However, there was no corresponding increase in the density or prevalence of total parasites or gametocyte prevalence.,The increase in gametocyte production during the pre-clinical period supports the hypothesis that P. falciparum may respond to environmental cues, such as mosquito biting, to modulate its transmission strategy.,Thus, seasonal changes may be important to ignite transmission in unstable-malaria settings.

Plasmodium falciparum immature gametocytes accumulate in the bone marrow, but their exact location in this tissue remains unclear.,The stage and deposition pattern of gametocytes was analysed on histological sections of a bone marrow sample collected in a patient with subacute P. falciparum malaria.,A majority (89%) of immature stages II to IV gametocytes and a minority (29%) of mature stage V gametocytes were observed in extravascular spaces.,These observations represent a valuable step towards understanding sequestration patterns of P. falciparum gametocytes and may ultimately lead to novel transmission-blocking interventions.

Strongyloides stercoralis and human T-lymphotropic virus 1 (HTLV-1) coinfections have been extensively reported in the literature, but the diagnosis and treatment of strongyloidiasis remains a challenge, particularly in HTLV-1 carriers.,Our objectives were to evaluate the efficacy of a new PCR method for the detection of S. stercoralis in HTLV-1-positive patients.,Stools were collected over a 1-year period across the endemic region of French Guiana, including remote forest areas.,Two systems of real-time PCR were then used comparatively, with small subunit and specific repeat as respective targets, and compared with the results of microscopic examinations.,One-hundred and twelve stool samples were included.,Twenty-seven patients (24.1%) presented a positive HTLV-1 serology.,The overall prevalence of strongyloidiasis among the 112 patients was 30% with small-subunit PCR and 11.6% with microscopic examinations.,In the seropositive population, all tested stools were negative, whereas 51.2% were positive using small-subunit PCR.,Thus, PCR allowed a much-improved sensitivity, particularly in HTLV-1 carriers.,Among the two systems investigated, small subunit yielded better results than specific repeat PCR, with prevalence rates in HTLV-1 carriers of 51.2% and 22.2%, respectively.,Therefore, PCR should be considered as a useful tool for the diagnosis of strongyloidiasis, particularly in HTLV-1 carriers who often present a light parasitic load due to erratic administration of anthelmintic drugs.

Strongyloides stercoralis is a widely distributed parasite that infects 30 to 100 million people worldwide.,In the United States strongyloidiasis is recognized as an important infection in immigrants and refugees.,Public health and commercial reference laboratories need a simple and reliable method for diagnosis of strongyloidiasis to identify and treat cases and to prevent transmission.,The recognized laboratory test of choice for diagnosis of strongyloidiasis is detection of disease specific antibodies, most commonly using a crude parasite extract for detection of IgG antibodies.,Recently, a luciferase tagged recombinant protein of S. stercoralis, Ss-NIE-1, has been used in a luciferase immunoprecipitation system (LIPS) to detect IgG and IgG4 specific antibodies.,To promote wider adoption of immunoassays for strongyloidiasis, we used the Ss-NIE-1 recombinant antigen without the luciferase tag and developed ELISA and fluorescent bead (Luminex) assays to detect S. stercoralis specific IgG4.,We evaluated the assays using well-characterized sera from persons with or without presumed strongyloidiasis.,The sensitivity and specificity of Ss-NIE-1 IgG4 ELISA were 95% and 93%, respectively.,For the IgG4 Luminex assay, the sensitivity and specificity were 93% and 95%, respectively.,Specific IgG4 antibody decreased after treatment in a manner that was similar to the decrease of specific IgG measured in the crude IgG ELISA.,The sensitivities of the Ss-NIE-1 IgG4 ELISA and Luminex assays were comparable to the crude IgG ELISA but with improved specificities.,However, the Ss-NIE-1 based assays are not dependent on native parasite materials and can be performed using widely available laboratory equipment.,In conclusion, these newly developed Ss-NIE-1 based immunoassays can be readily adopted by public health and commercial reference laboratories for routine screening and clinical diagnosis of S. stercoralis infection in refugees and immigrants in the United States.

Visceral leishmaniasis (VL) remains a serious public health problem in China.,To explore the temporal, spatial, and spatiotemporal characteristics of visceral leishmaniasis (VL), the spatial and spatiotemporal clustering distribution and their relationships with the surrounding geographic environmental factors were analyzed.,In this study, the average nearest-neighbor distance (ANN), Ripley’s K-function and Moran’s I statistics were used to evaluate spatial autocorrelation in the VL distribution of the existing case patterns.,Getis-Ord Gi* was used to identify the hot-spot and cold-spot areas based on Geographic Information System (GIS), and spatiotemporal retrospective permutation scan statistics was used to detect the spatiotemporal clusters.,The results indicated that VL continues to be a serious public health problem in Kashi Prefecture, China, particularly in the north-central region of Jiashi County, which is a relatively high-risk area in which hot spots are distributed.,Autumn and winter months were the outbreak season for VL cases.,The detection of spatial and spatiotemporal patterns can provide epidemiologists and local governments with significant information for prevention measures and control strategies.

Kashi Prefecture of Xinjiang is one of the most seriously affected areas with anthroponotic visceral leishmaniasis in China.,A better understanding of space distribution features in this area was needed to guide strategies to eliminate visceral leishmaniasis from highly endemic areas.,We performed a spatial analysis using the data collected in Bosh Klum Township in Xinjiang China.,Based on the report of endemic diseases between 1990 and 2005, three villages with a high number of visceral leishmaniasis cases in Bosh Klum Township were selected.,We conducted a household survey to collect the baseline data of kala-azar patients using standard case definitions.,The geographical information was recorded with GIS equipment.,A binomial distribution fitting test, runs test, and Scan statistical analysis were used to assess the space distribution of the study area.,The result of the binomial distribution fitting test showed that the distribution of visceral leishmaniasis cases in local families was inconsistent (χ2 = 53.23, P < 0.01).,The results of runs test showed that the distribution of leishmaniasis infected families along the channel was not random in the group of more than five infected families.,The proportion of this kind of group in all infected families was 63.84 % (113 of 177).,In the Scan statistical analysis, spatial aggregation was analyzed by poisson model, which found 3 spatial distribution areas 1) Zone A was located in a center point of 76.153447°E, 39.528477°N within its 1.11 mile radius, where the cumulative life-incidence of leishmaniasis was 1.95 times as high as that in surrounding areas (P < 0.05); 2) Zone B was located in a center point of 76.111968°E, 39.531895°N within its 0.54 mile radius, where the cumulative life-incidence of leishmaniasis was 1.82 times as high as that in surrounding areas (P < 0.01); and 3) Zone C was located in a center point of 76.195427°E, 39.563835°N within its 0.68 mile radius, where the cumulative life-incidence of leishmaniasis was 1.31 times as high as that in surrounding areas (P < 0.05).,The spatial distribution of visceral leishmaniasis-infected families was clustered.,Thus, the proper use of this finding would be an improvement in highly endemic areas, which could help identify the types of endemic areas and population at high risk and carry out appropriate measures to prevent and control VL in this area as well.

Differentiation between distinct stages is fundamental for the life cycle of intracellular protozoan parasites and for transmission between hosts, requiring stringent spatial and temporal regulation.,Here, we apply kinome-wide gene deletion and gene tagging in Leishmania mexicana promastigotes to define protein kinases with life cycle transition roles.,Whilst 162 are dispensable, 44 protein kinase genes are refractory to deletion in promastigotes and are likely core genes required for parasite replication.,Phenotyping of pooled gene deletion mutants using bar-seq and projection pursuit clustering reveal functional phenotypic groups of protein kinases involved in differentiation from metacyclic promastigote to amastigote, growth and survival in macrophages and mice, colonisation of the sand fly and motility.,This unbiased interrogation of protein kinase function in Leishmania allows targeted investigation of organelle-associated signalling pathways required for successful intracellular parasitism.,Protein kinases are fundamental in cellular signalling required for Leishmania survival throughout the life cycle.,Here, Baker and Catta-Preta et al. report on a kinome-wide functional study in Leishmania mexicana to define protein kinases with roles in life cycle transition.

During malaria infection, Plasmodium spp. parasites are cyclically invading red blood cells (RBCs) where they can follow two different developmental pathways: replicate asexually to sustain the infection or differentiate into gametocytes - sexual stages which can be taken by a mosquito ultimately leading to disease transmission.,Despite its key importance for malaria control, the process of gametocytogenesis remains poorly understood, partially due to the difficulty of generating high numbers of sexually committed parasites in laboratory conditions1.,Recently an apicomplexa-specific transcription factor (AP2-G) was identified as necessary for gametocyte production in multiple Plasmodium species2,3.and suggested to be an epigenetically regulated master switch initiating gametocytogenesis4,5.,Here we show that in a rodent malaria parasite Plasmodium berghei conditional overexpression of AP2-G can be used to synchronously convert the great majority of the population into fertile gametocytes.,This discovery allowed us to redefine the time frame of sexual commitment, identify a number of putative AP2-G targets and chart the sequence of transcriptional changes through the gametocyte development including the observation that gender partitioned transcription within 6 h of induction.,These data provide entry points for further detailed characterization of the key process required for malaria transmission.

Since the year 2000, a concerted campaign against malaria has led to unprecedented levels of intervention coverage across sub-Saharan Africa.,Understanding the effect of this control effort is vital to inform future control planning.,However, the effect of malaria interventions across the varied epidemiological settings of Africa remains poorly understood owing to the absence of reliable surveillance data and the simplistic approaches underlying current disease estimates.,Here we link a large database of malaria field surveys with detailed reconstructions of changing intervention coverage to directly evaluate trends from 2000 to 2015 and quantify the attributable effect of malaria disease control efforts.,We found that Plasmodium falciparum infection prevalence in endemic Africa halved and the incidence of clinical disease fell by 40% between 2000 and 2015.,We estimate that interventions have averted 663 (542-753 credible interval) million clinical cases since 2000.,Insecticide-treated nets, the most widespread intervention, were by far the largest contributor (68% of cases averted).,Although still below target levels, current malaria interventions have substantially reduced malaria disease incidence across the continent.,Increasing access to these interventions, and maintaining their effectiveness in the face of insecticide and drug resistance, should form a cornerstone of post-2015 control strategies.

Insecticide-treated nets (ITNs) for malaria control are widespread but coverage remains inadequate.,We developed a Bayesian model using data from 102 national surveys, triangulated against delivery data and distribution reports, to generate year-by-year estimates of four ITN coverage indicators.,We explored the impact of two potential 'inefficiencies': uneven net distribution among households and rapid rates of net loss from households.,We estimated that, in 2013, 21% (17%-26%) of ITNs were over-allocated and this has worsened over time as overall net provision has increased.,We estimated that rates of ITN loss from households are more rapid than previously thought, with 50% lost after 23 (20-28) months.,We predict that the current estimate of 920 million additional ITNs required to achieve universal coverage would in reality yield a lower level of coverage (77% population access).,By improving efficiency, however, the 920 million ITNs could yield population access as high as 95%.,DOI:http://dx.doi.org/10.7554/eLife.09672.001,Malaria is a major cause of death in many parts of the world, especially in sub-Saharan Africa.,Recently, there has been a renewed emphasis on using preventive measures to reduce the deaths and illnesses caused by malaria.,Insecticide-treated nets are the most prominent preventive measure used in areas where malaria is particularly common.,However, despite huge international efforts to send enough nets to the regions that need them, the processes of delivering and distributing the nets are inefficient.,This problem is compounded by the fact that little information is available on how many nets people actually own and use within each country.,`,Bhatt et al. have now created a mathematical model that describes the use and distribution of nets across Africa since 2000.,This is based on data collected from national surveys and reports on the delivery and distribution of the nets.,The model estimates that in 2013, only 43% of people at risk of malaria slept under a net.,Furthermore, 21% of new nets were allocated to households that already had enough nets, an inefficiency that has worsened over the years.,Nets are also lost from households much more rapidly than previously thought.,It’s currently estimated that 920 million additional nets are required to ensure that everyone at risk from malaria in Africa is adequately protected.,However, Bhatt et al.’s model suggests that given the current inefficiencies in net distribution, the extra nets would in reality protect a much smaller proportion of the population.,Taking measures to more effectively target the nets to the households that need them could improve this coverage level to 95% of the population.,The next challenge is to devise distribution strategies to send nets to where they are most needed.,DOI:http://dx.doi.org/10.7554/eLife.09672.002

We review emerging and re-emerging diseases such as schistosomiasis, dengue, avian influenza, angiostrongyliasis and soil-transmitted helminthiasis that occurre in China, with particular emphasis on environmental and agricultural change.,•We discuss the emergence and re-emergence of infectious diseases in developing countries.,•Changes in the natural environment and agricultural systems, govern infectious diseases.,•Case studies are presented from China.,•Research priorities and response strategies, are offered for consideration.,We discuss the emergence and re-emergence of infectious diseases in developing countries.,Changes in the natural environment and agricultural systems, govern infectious diseases.,Case studies are presented from China.,Research priorities and response strategies, are offered for consideration.,Changes in the natural environment and agricultural systems induced by economic and industrial development, including population dynamics (growth, urbanization, migration), are major causes resulting in the persistence, emergence and re-emergence of infectious diseases in developing countries.,In the face of rapid demographic, economic and social transformations, the People's Republic of China (P.R.,China) is undergoing unprecedented environmental and agricultural change.,We review emerging and re-emerging diseases such as schistosomiasis, dengue, avian influenza, angiostrongyliasis and soil-transmitted helminthiasis that have occurred in P.R.,China due to environmental and agricultural change.,This commentary highlights the research priorities and the response strategies, namely mitigation and adaptation, undertaken to eliminate the resurgence of those infectious diseases.

Schistosomiasis japonica, caused by Schistosoma japonicum infection, remains a major public health concern in China, and the geographical distribution of this neglected tropical disease is limited to regions where Oncomelania hupensis, the intermediate host of the causative parasite, is detected.,The purpose of this study was to monitor the transmission of S. japonicum in potential risk regions of China during the period from 2008 through 2012.,To monitor the transmission, 10 fixed surveillance sites and 30 mobile sentinel sites were selected in 10 counties of four provinces, namely Anhui, Jiangsu, Chongqing and Hubei.,There were 8, 9, 6, 2 and 3 cases infected with S. japonicum detected in the 30 mobile sentinel sites during the 5-year study period, while 27 subjects were positive for the antibody-based serum test in the 10 fixed sentinel sites; however, no infection was found.,In addition, neither local nor imported livestock were found to be infected.,No O. hupensis snails were detected in either the fixed surveillance or the mobile sentinel sites; however, the snail host was found to survive and reproduce at Chaohu Lake, inferring the potential of transmission of the disease.,It is suggested that the continuous surveillance of schistosomiasis japonica should be carried out in both the endemic foci and potential risk regions of China, and an active, sensitive system to respond the potential risk of transmission seems justified.

The lack of a continuous long-term in vitro culture system for Plasmodium vivax severely limits our knowledge of pathophysiology of the most widespread malaria parasite.,To gain direct understanding of P. vivax human infections, we used Next Generation Sequencing data mining to unravel parasite in vivo expression profiles for P. vivax, and P. falciparum as comparison.,We performed cloud and local computing to extract parasite transcriptomes from publicly available raw data of human blood samples.,We developed a Poisson Modelling (PM) method to confidently identify parasite derived transcripts in mixed RNAseq signals of infected host tissues.,We successfully retrieved and reconstructed parasite transcriptomes from infected patient blood as early as the first blood stage cycle; and the same methodology did not recover any significant signal from controls.,Surprisingly, these first generation blood parasites already show strong signature of transmission, which indicates the commitment from asexual-to-sexual stages.,Further, we place the results within the context of P. vivax’s complex life cycle, by developing mathematical models for P. vivax and P. falciparum and using sensitivity analysis assess the relative epidemiological impact of possible early stage transmission.,The study uncovers the earliest onset of P. vivax blood pathogenesis and highlights the challenges of P. vivax eradication programs.,The online version of this article (10.1186/s12918-018-0669-4) contains supplementary material, which is available to authorized users.

Malaria is a major cause of anaemia in tropical areas.,Malaria infection causes haemolysis of infected and uninfected erythrocytes and bone marrow dyserythropoiesis which compromises rapid recovery from anaemia.,In areas of high malaria transmission malaria nearly all infants and young children, and many older children and adults have a reduced haemoglobin concentration as a result.,In these areas severe life-threatening malarial anaemia requiring blood transfusion in young children is a major cause of hospital admission, particularly during the rainy season months when malaria transmission is highest.,In severe malaria, the mortality rises steeply below an admission haemoglobin of 3 g/dL, but it also increases with higher haemoglobin concentrations approaching the normal range.,In the management of severe malaria transfusion thresholds remain uncertain.,Prevention of malaria by vector control, deployment of insecticide-treated bed nets, prompt and accurate diagnosis of illness and appropriate use of effective anti-malarial drugs substantially reduces the burden of anaemia in tropical countries.

Canine leishmaniosis (CanL) is an important zoonotic parasitic disease, endemic in the Mediterranean basin.,In this region, transmission of Leishmania infantum, the etiological agent of CanL, is through the bite of phlebotomine sand flies.,Therefore, monitoring host-vector contact represents an important epidemiological tool, and could be used to assess the effectiveness of vector-control programmes in endemic areas.,Previous studies have shown that canine antibodies against the saliva of phlebotomine sand flies are specific markers of exposure to Leishmania vectors.,However, this method needs to be further validated in natural heterogeneous dog populations living in CanL endemic areas.,In this study, 176 dogs living in 12 different locations of an L. infantum endemic area in north-east Spain were followed for 14 months.,Blood samples were taken at 5 pre-determined time points (February, August and October 2016; January and April 2017) to assess the canine humoral immune response to whole salivary gland homogenate (SGH) and to the single salivary 43 kDa yellow-related recombinant protein (rSP03B) of Phlebotomus perniciosus, a proven vector of L. infantum naturally present in this region.,Simultaneously, in all dogs, L. infantum infection status was assessed by serology.,The relationship between anti-SGH and anti-rSP03B antibodies with the sampling month, L. infantum infection and the location was tested by fitting multilevel linear regression models.,The dynamics of canine anti-saliva IgG for both SGH and rSP03B followed the expected trends of P. perniciosus activity in the region.,Statistically significant associations were detected for both salivary antigens between vector exposure and sampling month or dog seropositivity to L. infantum.,The correlation between canine antibodies against SGH and rSP03B was moderate.,Our results confirm the frequent presence of CanL vectors in the study area in Spain and support the applicability of SGH- and rSP03B-based ELISA tests to study canine exposure to P. perniciosus in L. infantum endemic areas.

A wide spectrum of clinical manifestations and immune responses exist in canine L. infantum infection.,Ibizan hounds are more “resistant” to disease than other dog breeds.,Recognition of pathogen-associated molecule patterns by toll like receptors (TLRs) rapidly triggers a variety of anti-microbial immune responses through the induction of pro-inflammatory cytokines such as TNF-α and IL-6 which may play an important role in controlling Leishmania infection.,The main objective of this study was to investigate and compare the effect of a TLR2 agonist (TLR2a) alone or in combination with L. infantum antigen (LSA) on ex vivo whole blood cytokine production from healthy seronegative IFN-γ non-producer dogs from an area of low in canine leishmaniosis endemicity (n = 11); sick seropositive dogs with low production of IFN-γ (n = 17) and healthy seronegative or low positive Ibizan hounds with a predominant IFN-γ production (n = 21) from a highly endemic area.,Whole blood was stimulated with medium alone (Ø), LSA, concanavalin A, TLR2 (Pam3CSK4) receptor agonist (Ø + TLR2a) and TLR2a and LSA (LSA + TLR2a) for 48 h.,Supernatants were harvested for measurement of canine TNF-α and IL-6 cytokines by ELISA.,A significant increase of TNF-α was found in the supernatants of stimulated blood from all groups (Ø + TLR2a and LSA + TLR2a) when compared with medium alone.,A similar pattern was observed for IL-6.,Interestingly, a significant increase of TNF-α production was only observed when stimulation with LSA + TLR2a was compared with TLR2a alone in Ibizan hounds.,A significant increase of TNF-α production was observed with stimulation of LSA + TLR2a when compared with LSA in all groups.,Significantly higher concentrations of TNF-α and IL-6 were detected in Ibizan hounds, especially for the Ø + TLR2a and LSA + TLR2a treatments compared with other groups.,This study demonstrated that TLR2a alone enhances the production of the inflammatory cytokines TNF-α and IL-6 in sick, “resistant” and healthy non-infected dogs.,In addition, a combination of LSA+TLR2a promoted a synergistic pro-inflammatory effect with TNF-α in Ibizan hounds but not in seropositive sick dogs and seronegative healthy dogs.,These findings might suggest the importance of Pam3CSK4 as a possible immunomodulator for CanL.,The online version of this article (doi:10.1186/s13071-017-2062-3) contains supplementary material, which is available to authorized users.

Further reduction in malaria prevalence and its eventual elimination would be greatly facilitated by the development of biomarkers of exposure and/or acquired immunity to malaria, as well as the deployment of effective vaccines against Plasmodium falciparum and Plasmodium vivax.,A better understanding of the acquisition of immunity in naturally-exposed populations is essential for the identification of antigens useful as biomarkers, as well as to inform rational vaccine development.,ELISA was used to measure total IgG to a synthetic form of glycosylphosphatidylinositol from P. falciparum (PfGPI) in a cohort of 1-3 years old Papua New Guinea children with well-characterized individual differences in exposure to P. falciparum and P. vivax blood-stage infections.,The relationship between IgG levels to PfGPI and measures of recent and past exposure to P. falciparum and P. vivax infections was investigated, as well as the association between antibody levels and prospective risk of clinical malaria over 16 months of follow-up.,Total IgG levels to PfGPI were low in the young children tested.,Antibody levels were higher in the presence of P. falciparum or P. vivax infections, but short-lived.,High IgG levels were associated with higher risk of P. falciparum malaria (IRR 1.33-1.66, P = 0.008-0.027), suggesting that they are biomarkers of increased exposure to P. falciparum infections.,Given the cross-reactive nature of antibodies to PfGPI, high IgG levels were also associated with reduced risk of P. vivax malaria (IRR 0.65-0.67, P = 0.039-0.044), indicating that these antibodies are also markers of acquired immunity to P. vivax.,This study highlights that in young children, IgG to PfGPI might be a useful marker of immune-status to both P. falciparum and P. vivax infections, and potentially useful to help malaria control programs to identify populations at-risk.,Further functional studies are necessary to confirm the potential of PfGPI as a target for vaccine development.,The online version of this article (doi:10.1186/s12936-017-2042-2) contains supplementary material, which is available to authorized users.

In areas mesoendemic for malaria transmission, symptomatic individuals play a significant role as reservoirs for malaria infection.,Understanding the pathogenesis of symptomatic malaria is important in devising tools for augmenting malaria control.,In this study, the effect of TLR9 polymorphisms on susceptibility to symptomatic malaria was investigated among Ghanaian children.,Four hundred and twenty nine (429) healthy Ghanaian children, aged three to eleven years (3-11 years), were enrolled into a cohort study and actively followed up for symptomatic malaria for one year.,Four TLR9 single nucleotide polymorphisms (SNPs) namely: rs187084 (C-1486 T), rs5743836(C-1237 T), rs352139 (G + 1174A) and rs352140 (G + 2848A) were genotyped by direct sequencing, and their attributable and relative risks for symptomatic malaria determined.,TLR9 haplotypes were inferred using the PHASE software and analysed for the risk of symptomatic malaria.,A luciferase assay was performed to investigate whether the TLR9 haplotypes influence TLR9 promoter activity.,The rs352139 GG genotype showed a significantly increased relative risk of 4.8 for symptomatic malaria (P = 0.0024) and a higher mean parasitaemia (P = 0.04).,Conversely, the rs352140 GG genotype showed a significantly reduced relative risk of 0.34 (P = 0.048).,TLR9 haplotypes analyses showed that TTAG haplotype was significantly associated with reduced relative risk of 0.2 for symptomatic malaria (P = 4×10-6) and a lower mean parasitaemia (0.007), while CTGA haplotype had an increased relative risk of 3.3 (P = 0.005).,Functional luciferase reporter gene expression assay revealed that the TTA haplotype had a significantly higher promoter activity than the CCG, CTG and TCG haplotypes.,Taken together, these findings indicate a significant association of TLR9 gene polymorphisms with symptomatic malaria among Ghanaian children in Dangme-West district.

The adaptation of malaria vectors to urban areas is becoming a serious challenge for malaria control.,The study presents the evolution of pyrethroid resistance in mosquito populations from the cities of Douala and Yaoundé between 2010 and 2013.,Susceptibility tests to permethrin and deltamethrin were carried out with two- to four-day old unfed Anopheles gambiae sensu lato adults raised from larvae collected from the field.,Mosquitoes resistant to permethrin and deltamethrin and control were screened to detect the presence of the kdr alleles using the TaqMan assays.,Mosquitoes belonging to the An. gambiae complex were subjected to PCR assays designed for species and molecular forms identifications.,The genomic region containing the upstream of intron-1 of the voltage-gated sodium channel was sequenced and compared between mosquitoes originating from different breeding habitats.,Anopheles gambiae s.l. specimens collected from the city of Douala were all Anopheles coluzzii.,In Yaoundé, both An. gambiae and An. coluzzii were recorded.,A rapid decrease of mosquito mortality to permethrin and deltamethrin was recorded between 2010 and 2013 in the two cities.,The mortality rate varied from 80.3 to 22.3% and 94.4 to 59.7% for permethrin and deltamethrin, respectively.,Both kdr alleles L1014F and L1014S were recorded.,The frequency of kdr alleles increased rapidly over the study period, varying from 44 to 88.9% in Yaoundé and from 68 to 81% in Douala.,The sequencing of a 1,228 bp region of intro-1 of the voltage-gated sodium channel revealed the presence of five different haplotypes.,A high number of these haplotypes were recorded in An. coluzzii samples.,No evidence for a recent selective sweep on intron-1 sequence within samples originating from different breeding habitat was detected using Fu’s and Tajima Fs statistics.,The present study supports rapid evolution of pyrethroid resistance in vector populations from the cities of Douala and Yaoundé and calls for immediate action to fight against the increasing prevalence of pyrethroid-resistant mosquitoes.

Establishing the extent, geographical distribution and mechanisms of insecticide resistance in malaria vectors is a prerequisite for resistance management.,Here, we report a widespread distribution of insecticide resistance in the major malaria vector An. funestus across Uganda and western Kenya under the control of metabolic resistance mechanisms.,Female An. funestus collected throughout Uganda and western Kenya exhibited a Plasmodium infection rate between 4.2 to 10.4%.,Widespread resistance against both type I (permethrin) and II (deltamethrin) pyrethroids and DDT was observed across Uganda and western Kenya.,All populations remain highly susceptible to carbamate, organophosphate and dieldrin insecticides.,Knockdown resistance plays no role in the pyrethroid and DDT resistance as no kdr mutation associated with resistance was detected despite the presence of a F1021C replacement.,Additionally, no signature of selection was observed on the sodium channel gene.,Synergist assays and qRT-PCR indicated that metabolic resistance plays a major role notably through elevated expression of cytochrome P450s.,DDT resistance mechanisms differ from West Africa as the L119F-GSTe2 mutation only explains a small proportion of the genetic variance to DDT resistance.,The extensive distribution of pyrethroid and DDT resistance in East African An. funestus populations represents a challenge to the control of this vector.,However, the observed carbamate and organophosphate susceptibility offers alternative solutions for resistance management.

Sensitive methods for detecting asymptomatic malaria infections are essential for identifying potential transmission reservoirs and obtaining an accurate assessment of malaria epidemiology in low-endemicity areas aiming to eliminate malaria.,PCR techniques to detect parasite nucleic acids (DNA or RNA) are among the most commonly used molecular methods.,However, most of these methods are of low throughput and cannot be used for large-scale molecular epidemiological studies.,A recently developed capture and ligation probe-PCR (CLIP-PCR) is claimed to have the sensitivity of molecular techniques and the high throughput capacity needed for screening purposes.,This study aimed to compare several molecular methods for detecting asymptomatic and submicroscopic Plasmodium infections in healthy residents of a malaria-hypoendemic region in Southeast Asia, where malaria elimination is in sight.,This study compared three molecular detection methods side-by-side, namely nested PCR targeting the rRNA genes, nested RT-PCR to detect parasite rRNA, and CLIP-PCR to detect parasite rRNA in 1005 healthy individuals in northeastern Myanmar.,For nested PCR and RT-PCR, parasite DNA and total RNA were extracted from ~100 µL of blood, whereas RNA used for CLIP-PCR was from a 3 mm disk of dried blood filter paper.,The sensitivity and specificity of these methods were compared with those of conventional light microscopy.,In addition, RT-PCR and quantitative RT-PCR (qRT-PCR) targeting the Pvs25 gene in Plasmodium vivax were used to assess gametocyte prevalence in the samples.,Light microscopy detected Plasmodium infections in only 1.19% of the residents harbouring the parasites.,CLIP-PCR had slightly better performance and detected Plasmodium infections in 1.89% of the population.,Further improvement was achieved by nested PCR to detect parasite DNA, which detected P. vivax and Plasmodium falciparum infections in 2.39% of the residents.,The nested RT-PCR targeting rRNA, however, detected as many as 187 (18.61%) individuals having Plasmodium infections with P. vivax being the predominant species (176 P. vivax, 5 P. falciparum and 6 P. falciparum/P. vivax mixed infections).,Of the 210 Plasmodium-positive samples detected by all molecular methods, 115 were Pvs25-positive by qRT-PCR, indicating that a large proportion of asymptomatic individuals were gametocyte carriers.,Nested RT-PCR based on the detection of asexual-stage parasite rRNA was the most sensitive, with a more than sixfold higher sensitivity than the other two molecular methods of parasite detection.,CLIP-PCR has an increased throughput, but its sensitivity in this study was much lower than those of other molecular methods, which may be partially due to the smaller amount of RNA input used.,The online version of this article (doi:10.1186/s12936-017-1813-0) contains supplementary material, which is available to authorized users.

Emergence of artemisinin resistance in southeast Asia poses a serious threat to the global control of Plasmodium falciparum malaria.,Discovery of the K13 marker has transformed approaches to the monitoring of artemisinin resistance, allowing introduction of molecular surveillance in remote areas through analysis of DNA.,We aimed to assess the spread of artemisinin-resistant P falciparum in Myanmar by determining the relative prevalence of P falciparum parasites carrying K13-propeller mutations.,We did this cross-sectional survey at malaria treatment centres at 55 sites in ten administrative regions in Myanmar, and in relevant border regions in Thailand and Bangladesh, between January, 2013, and September, 2014.,K13 sequences from P falciparum infections were obtained mainly by passive case detection.,We entered data into two geostatistical models to produce predictive maps of the estimated prevalence of mutations of the K13 propeller region across Myanmar.,Overall, 371 (39%) of 940 samples carried a K13-propeller mutation.,We recorded 26 different mutations, including nine mutations not described previously in southeast Asia.,In seven (70%) of the ten administrative regions of Myanmar, the combined K13-mutation prevalence was more than 20%.,Geospatial mapping showed that the overall prevalence of K13 mutations exceeded 10% in much of the east and north of the country.,In Homalin, Sagaing Region, 25 km from the Indian border, 21 (47%) of 45 parasite samples carried K13-propeller mutations.,Artemisinin resistance extends across much of Myanmar.,We recorded P falciparum parasites carrying K13-propeller mutations at high prevalence next to the northwestern border with India.,Appropriate therapeutic regimens should be tested urgently and implemented comprehensively if spread of artemisinin resistance to other regions is to be avoided.,Wellcome Trust-Mahidol University-Oxford Tropical Medicine Research Programme and the Bill & Melinda Gates Foundation.

Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) interventions can reduce malaria transmission by targeting mosquitoes when they feed upon sleeping humans and/or rest inside houses, livestock shelters or other man-made structures.,However, many malaria vector species can maintain robust transmission, despite high coverage of LLINs/IRS containing insecticides to which they are physiologically fully susceptible, because they exhibit one or more behaviours that define the biological limits of achievable impact with these interventions: (1) Natural or insecticide-induced avoidance of contact with treated surfaces within houses and early exit from them, thus minimizing exposure hazard of vectors which feed indoors upon humans; (2) Feeding upon humans when they are active and unprotected outdoors, thereby attenuating personal protection and any consequent community-wide suppression of transmission; (3) Feeding upon animals, thus minimizing contact with insecticides targeted at humans or houses; (4) Resting outdoors, away from insecticide-treated surfaces of nets, walls and roofs.,Residual malaria transmission is, therefore, defined as all forms of transmission that can persist after achieving full universal coverage with effective LLINs and/or IRS containing active ingredients to which local vector populations are fully susceptible.,Residual transmission is sufficiently intense across most of the tropics to render malaria elimination infeasible without new or improved vector control methods.,Many novel or improved vector control strategies to address residual transmission are emerging that either: (1) Enhance control of adult vectors that enter houses to feed and/or rest by killing, repelling or excluding them; (2) Kill or repel adult mosquitoes when they attack people outdoors; (3) Kill adult mosquitoes when they attack livestock; (4) Kill adult mosquitoes when they feed upon sugar or; (5) Kill immature mosquitoes in aquatic habitats.,To date, none of these options has sufficient supporting evidence to justify full-scale programmatic implementation.,Concerted investment in their rigorous selection, development and evaluation is required over the coming decade to enable control and, ultimately, elimination of residual malaria transmission.,In the meantime, national programmes may assess options for addressing residual transmission under programmatic conditions through pilot studies with strong monitoring, evaluation and operational research components, similar to the Onchocerciasis Control Programme.

In line with the Global trend to improve malaria control efforts a major campaign of insecticide treated net distribution was initiated in 1999 and indoor residual spraying with DDT or pyrethroids was reintroduced in 2000 in Zambia.,In 2006, these efforts were strengthened by the President's Malaria Initiative.,This manuscript reports on the monitoring and evaluation of these activities and the potential impact of emerging insecticide resistance on disease transmission.,Mosquitoes were captured daily through a series of 108 window exit traps located at 18 sentinel sites.,Specimens were identified to species and analyzed for sporozoites.,Adult Anopheles mosquitoes were collected resting indoors and larva collected in breeding sites were reared to F1 and F0 generations in the lab and tested for insecticide resistance following the standard WHO susceptibility assay protocol.,Annual cross sectional household parasite surveys were carried out to monitor the impact of the control programme on prevalence of Plasmodium falciparum in children aged 1 to 14 years.,A total of 619 Anopheles gambiae s.l. and 228 Anopheles funestus s.l. were captured from window exit traps throughout the period, of which 203 were An. gambiae malaria vectors and 14 An. funestus s.s..,In 2010 resistance to DDT and the pyrethroids deltamethrin, lambda-cyhalothrin and permethrin was detected in both An. gambiae s.s. and An. funestus s.s..,No sporozoites were detected in either species.,Prevalence of P. falciparum in the sentinel sites remained below 10% throughout the study period.,Both An. gambiae s.s. and An. funestus s.s. were controlled effectively with the ITN and IRS programme in Zambia, maintaining a reduced disease transmission and burden.,However, the discovery of DDT and pyrethroid resistance in the country threatens the sustainability of the vector control programme.

Background: Malaria continues to be a major public health concern in Africa.,Approximately 3.2 billion people worldwide are still at risk of contracting malaria, and 80% of deaths caused by malaria are concentrated in only 15 countries, most of which are in Africa.,These high-burden countries have achieved a lower than average reduction of malaria incidence and mortality, and Mozambique is among these countries.,Malaria eradication is therefore one of Mozambique’s main priorities.,Few studies on malaria have been carried out in Chimoio, and there is no malaria map risk of the area.,This map is important to identify areas at risk for application of Public Precision Health approaches.,By using GIS-based spatial modelling techniques, the research goal of this article was to map and model malaria risk areas using climate, socio-demographic and clinical variables in Chimoio, Mozambique.,Methods: A 30 m × 30 m Landsat image, ArcGIS 10.2 and BioclimData were used.,A conceptual model for spatial problems was used to create the final risk map.,The risks factors used were: the mean temperature, precipitation, altitude, slope, distance to water bodies, distance to roads, NDVI, land use and land cover, malaria prevalence and population density.,Layers were created in a raster dataset.,For class value comparisons between layers, numeric values were assigned to classes within each map layer, giving them the same importance.,The input dataset were ranked, with different weights according to their suitability.,The reclassified outputs of the data were combined.,Results: Chimoio presented 96% moderate risk and 4% high-risk areas.,The map showed that the central and south-west “Residential areas”, namely, Centro Hipico, Trangapsso, Bairro 5 and 1° de Maio, had a high risk of malaria, while the rest of the residential areas had a moderate risk.,Conclusions: The entire Chimoio population is at risk of contracting malaria, and the precise estimation of malaria risk, therefore, has important precision public health implications and for the planning of effective control measures, such as the proper time and place to spray to combat vectors, distribution of bed nets and other control measures.

Transmission intensity affects almost all aspects of malaria epidemiology and the impact of malaria on human populations.,Maps of transmission intensity are necessary to identify populations at different levels of risk and to evaluate objectively options for disease control.,To remain relevant operationally, such maps must be updated frequently.,Following the first global effort to map Plasmodium falciparum malaria endemicity in 2007, this paper describes the generation of a new world map for the year 2010.,This analysis is extended to provide the first global estimates of two other metrics of transmission intensity for P. falciparum that underpin contemporary questions in malaria control: the entomological inoculation rate (PfEIR) and the basic reproductive number (PfR).,Annual parasite incidence data for 13,449 administrative units in 43 endemic countries were sourced to define the spatial limits of P. falciparum transmission in 2010 and 22,212 P. falciparum parasite rate (PfPR) surveys were used in a model-based geostatistical (MBG) prediction to create a continuous contemporary surface of malaria endemicity within these limits.,A suite of transmission models were developed that link PfPR to PfEIR and PfR and these were fitted to field data.,These models were combined with the PfPR map to create new global predictions of PfEIR and PfR.,All output maps included measured uncertainty.,An estimated 1.13 and 1.44 billion people worldwide were at risk of unstable and stable P. falciparum malaria, respectively.,The majority of the endemic world was predicted with a median PfEIR of less than one and a median PfRc of less than two.,Values of either metric exceeding 10 were almost exclusive to Africa.,The uncertainty described in both PfEIR and PfR was substantial in regions of intense transmission.,The year 2010 has a particular significance as an evaluation milestone for malaria global health policy.,The maps presented here contribute to a rational basis for control and elimination decisions and can serve as a baseline assessment as the global health community looks ahead to the next series of milestones targeted at 2015.

Herein, we summarize what we consider are major contributions resulting from the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) program, including its key findings and key messages from those findings.,Briefly, SCORE’s key findings are as follows: i) biennial mass drug administration (MDA) with praziquantel can control schistosomiasis to moderate levels of prevalence; ii) MDA alone will not achieve elimination; iii) to attain and sustain control throughout endemic areas, persistent hotspots need to be identified following a minimal number of years of annual MDA and controlled through adaptive strategies; iv) annual MDA is more effective than biennial MDA in high-prevalence areas; v) the current World Health Organization thresholds for decision-making based on the prevalence of heavy infections should be redefined; and vi) point-of-care circulating cathodic antigen urine assays are useful for Schistosoma mansoni mapping in low-to-moderate prevalence areas.,The data and specimens collected and curated through SCORE efforts will continue to be critical resource for future research.,Besides providing useful information for program managers and revision of guidelines for schistosomiasis control and elimination, SCORE research and outcomes have identified additional questions that need to be answered as the schistosomiasis community continues to implement effective, evidence-based programs.,An overarching contribution of SCORE has been increased cohesiveness within the schistosomiasis field-oriented community, thereby fostering new and productive collaborations.,Based on SCORE’s findings and experiences, we propose new approaches, thresholds, targets, and goals for control and elimination of schistosomiasis, and recommend research and evaluation activities to achieve these targets and goals.

The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was established in 2008 to answer strategic questions about schistosomiasis control.,For programme managers, a high-priority question is: what are the most cost-effective strategies for delivering preventive chemotherapy (PCT) with praziquantel (PZQ)?,This paper describes the process SCORE used to transform this question into a harmonized research protocol, the study design for answering this question, the village eligibility assessments and data resulting from the first year of the study.,Beginning in 2009, SCORE held a series of meetings to specify empirical questions and design studies related to different schedules of PCT for schistosomiasis control in communities with high (gaining control studies) and moderate (sustaining control studies) prevalence of Schistosoma infection among school-aged children.,Seven studies are currently being implemented in five African countries.,During the first year, villages were screened for eligibility, and data were collected on prevalence and intensity of infection prior to randomisation and the implementation of different schemes of PZQ intervention strategies.,These studies of different treatment schedules with PZQ will provide the most comprehensive data thus far on the optimal frequency and continuity of PCT for schistosomiasis infection and morbidity control.,We expect that the study outcomes will provide data for decision-making for country programme managers and a rich resource of information to the schistosomiasis research community.,The trials are registered at International Standard Randomised Controlled Trial registry (identifiers: ISRCTN99401114, ISRCTN14849830, ISRCTN16755535, ISRCTN14117624, ISRCTN95819193 and ISRCTN32045736).

The intracellular human protozoan parasite Toxoplasma gondii uses a novel secreted protein to recruit host mitochondria and alter the host's response to infection.,Recent information has revealed the functional diversity and importance of mitochondria in many cellular processes including orchestrating the innate immune response.,Intriguingly, several infectious agents, such as Toxoplasma, Legionella, and Chlamydia, have been reported to grow within vacuoles surrounded by host mitochondria.,Although many hypotheses have been proposed for the existence of host mitochondrial association (HMA), the causes and biological consequences of HMA have remained unanswered.,Here we show that HMA is present in type I and III strains of Toxoplasma but missing in type II strains, both in vitro and in vivo.,Analysis of F1 progeny from a type II×III cross revealed that HMA is a Mendelian trait that we could map.,We use bioinformatics to select potential candidates and experimentally identify the polymorphic parasite protein involved, mitochondrial association factor 1 (MAF1).,We show that introducing the type I (HMA+) MAF1 allele into type II (HMA−) parasites results in conversion to HMA+ and deletion of MAF1 in type I parasites results in a loss of HMA.,We observe that the loss and gain of HMA are associated with alterations in the transcription of host cell immune genes and the in vivo cytokine response during murine infection.,Lastly, we use exogenous expression of MAF1 to show that it binds host mitochondria and thus MAF1 is the parasite protein directly responsible for HMA.,Our findings suggest that association with host mitochondria may represent a novel means by which Toxoplasma tachyzoites manipulate the host.,The existence of naturally occurring HMA+ and HMA− strains of Toxoplasma, Legionella, and Chlamydia indicates the existence of evolutionary niches where HMA is either advantageous or disadvantageous, likely reflecting tradeoffs in metabolism, immune regulation, and other functions of mitochondria.

Secretory polymorphic serine/threonine kinases control pathogenesis of Toxoplasma gondii in the mouse.,Genetic studies show that the pseudokinase ROP5 is essential for acute virulence, but do not reveal its mechanism of action.,Here we demonstrate that ROP5 controls virulence by blocking IFN-γ mediated clearance in activated macrophages.,ROP5 was required for the catalytic activity of the active S/T kinase ROP18, which phosphorylates host immunity related GTPases (IRGs) and protects the parasite from clearance.,ROP5 directly regulated activity of ROP18 in vitro, and both proteins were necessary to avoid IRG recruitment and clearance in macrophages.,Clearance of both the Δrop5 and Δrop18 mutants was reversed in macrophages lacking Irgm3, which is required for IRG function, and the virulence defect was fully restored in Irgm3−/− mice.,Our findings establish that the pseudokinase ROP5 controls the activity of ROP18, thereby blocking IRG mediated clearance in macrophages.,Additionally, ROP5 has other functions that are also Irgm3 and IFN-γ dependent, indicting it plays a general role in governing virulence factors that block immunity.

Malaria and schistosomiasis are major parasitic diseases causing morbidity and mortality in the tropics.,Epidemiological surveys have revealed coinfection rates of up to 30% among children in Sub-Saharan Africa.,To investigate the impact of coinfection of these two parasites on disease epidemiology and pathology, we carried out coinfection studies using Plasmodium yoelii and Schistosoma mansoni in mice.,Malaria parasite growth in the liver following sporozoite inoculation is significantly inhibited in mice infected with S. mansoni, so that when low numbers of sporozoites are inoculated, there is a large reduction in the percentage of mice that go on to develop blood stage malaria.,Furthermore, gametocyte infectivity is much reduced in mice with S. mansoni infections.,These results have profound implications for understanding the interactions between Plasmodium and Schistosoma species, and have implications for the control of malaria in schistosome endemic areas.

Diverse enteropathogen exposures associate with childhood malnutrition.,To elucidate mechanistic pathways whereby enteric microbes interact during malnutrition, we used protein deficiency in mice to develop a new model of co-enteropathogen enteropathy.,Focusing on common enteropathogens in malnourished children, Giardia lamblia and enteroaggregative Escherichia coli (EAEC), we provide new insights into intersecting pathogen-specific mechanisms that enhance malnutrition.,We show for the first time that during protein malnutrition, the intestinal microbiota permits persistent Giardia colonization and simultaneously contributes to growth impairment.,Despite signals of intestinal injury, such as IL1α, Giardia-infected mice lack pro-inflammatory intestinal responses, similar to endemic pediatric Giardia infections.,Rather, Giardia perturbs microbial host co-metabolites of proteolysis during growth impairment, whereas host nicotinamide utilization adaptations that correspond with growth recovery increase.,EAEC promotes intestinal inflammation and markers of myeloid cell activation.,During co-infection, intestinal inflammatory signaling and cellular recruitment responses to EAEC are preserved together with a Giardia-mediated diminishment in myeloid cell activation.,Conversely, EAEC extinguishes markers of host energy expenditure regulatory responses to Giardia, as host metabolic adaptations appear exhausted.,Integrating immunologic and metabolic profiles during co-pathogen infection and malnutrition, we develop a working mechanistic model of how cumulative diet-induced and pathogen-triggered microbial perturbations result in an increasingly wasted host.

Despite ongoing efforts, a highly effective vaccine against Plasmodium falciparum remains elusive.,Vaccines targeting the pre-erythrocytic stages of the P. falciparum life cycle are the most advanced to date, affording moderate levels of efficacy in field trials.,However, the discovery that the members of the merozoite PfRH5-PfCyRPA-PfRipr (RCR) complex are capable of inducing strain-transcendent neutralizing antibodies has renewed enthusiasm for the possibility of preventing disease by targeting the parasite during the blood stage of infection.,With Phase I/II clinical trials now underway using first-generation vaccines against PfRH5, and more on the horizon for PfCyRPA and PfRipr, this review explores the rationale and future potential of the RCR complex as a P. falciparum vaccine target.,The antigens PfRH5, PfCyRPA, and PfRipr can induce strain-transcendent neutralizing antibodies, and all three targets are essential and highly conserved.PfRH5, PfCyRPA, and PfRipr form a stable complex (RCR) that is involved in the induction of an erythrocytic calcium spike during merozoite invasion.Passive transfer of anti-CyRPA and anti-PfRH5 antibodies can protect against blood-stage P. falciparum in animal models.Structural studies have mapped out the first known critical inhibitory epitopes on PfRH5 and PfCyRPA which can be used for next-generation vaccine design.Early results from the first PfRH5 vaccine clinical trials have been reported with more anticipated soon, which will help guide the development of RCR-based vaccines.,The antigens PfRH5, PfCyRPA, and PfRipr can induce strain-transcendent neutralizing antibodies, and all three targets are essential and highly conserved.,PfRH5, PfCyRPA, and PfRipr form a stable complex (RCR) that is involved in the induction of an erythrocytic calcium spike during merozoite invasion.,Passive transfer of anti-CyRPA and anti-PfRH5 antibodies can protect against blood-stage P. falciparum in animal models.,Structural studies have mapped out the first known critical inhibitory epitopes on PfRH5 and PfCyRPA which can be used for next-generation vaccine design.,Early results from the first PfRH5 vaccine clinical trials have been reported with more anticipated soon, which will help guide the development of RCR-based vaccines.

Effective vaccines to combat malaria are urgently needed, but have proved elusive in the absence of validated correlates of natural immunity.,Repeated blood stage infections induce antibodies considered to be the main arbiters of protection from pathology, but their essential functions have remained speculative.,This study evaluated antibody dependent respiratory burst (ADRB) activity in polymorphonuclear neutrophils (PMN) induced by Plasmodium falciparum merozoites and antibodies in the sera of two different African endemic populations, and investigated its association with naturally acquired clinical protection.,Respiratory bursts by freshly isolated PMN were quantified by chemiluminescence readout in the presence of isoluminol, which preferentially detects extra-cellular reactive oxygen species (ROS).,Using a standardized, high throughput protocol, 230 sera were analyzed from individuals of all age groups living in meso- (Ndiop) or holo-endemic (Dielmo) Senegalese villages, and enrolled in a cross-sectional prospective study with intensive follow-up.,Statistical significance was determined using non-parametric tests and Poisson regression models.,The most important finding was that PMN ADRB activity was correlated with acquired clinical protection from malaria in both high and low transmission areas (P = 0.006 and 0.036 respectively).,Strikingly, individuals in Dielmo with dichotomized high ADRB indexes were seventeen fold less susceptible to malaria attacks (P = 0.006).,Complementary results showed that ADRB activity was (i) dependent on intact merozoites and IgG opsonins, but not parasitized erythrocytes, or complement, (ii) correlated with merozoite specific cytophilic IgG1 and IgG3 antibody titers (P<0.001 for both), and (iii) stronger in antisera from a holo-endemic compared to a meso-endemic site (P = 0.002), and reduced in asymptomatic carriers (P<0.001).,This work presents the first clearly demonstrated functional antibody immune correlate of clinical protection from Plasmodium falciparum malaria, and begs the question regarding the importance of ADRB by PMN for immune protection against malaria in vivo.

Plasmodium simium, a malaria parasite of non-human primates (NHP), was recently shown to cause zoonotic infections in humans in Brazil.,We sequenced the P. simium genome to investigate its evolutionary history and to identify any genetic adaptions that may underlie the ability of this parasite to switch between host species.,Phylogenetic analyses based on whole genome sequences of P. simium from humans and NHPs reveals that P. simium is monophyletic within the broader diversity of South American Plasmodium vivax, suggesting P. simium first infected NHPs as a result of a host switch of P. vivax from humans.,The P. simium isolates show the closest relationship to Mexican P. vivax isolates.,Analysis of erythrocyte invasion genes reveals differences between P. vivax and P. simium, including large deletions in the Duffy-binding protein 1 (DBP1) and reticulocyte-binding protein 2a genes of P. simium.,Analysis of P. simium isolated from NHPs and humans revealed a deletion of 38 amino acids in DBP1 present in all human-derived isolates, whereas NHP isolates were multi-allelic.,Analysis of the P. simium genome confirmed a close phylogenetic relationship between P. simium and P. vivax, and suggests a very recent American origin for P. simium.,The presence of the DBP1 deletion in all human-derived isolates tested suggests that this deletion, in combination with other genetic changes in P. simium, may facilitate the invasion of human red blood cells and may explain, at least in part, the basis of the recent zoonotic infections.,The online version contains supplementary material available at 10.1186/s12915-021-01139-5.

The lack of a continuous long-term in vitro culture system for Plasmodium vivax severely limits our knowledge of pathophysiology of the most widespread malaria parasite.,To gain direct understanding of P. vivax human infections, we used Next Generation Sequencing data mining to unravel parasite in vivo expression profiles for P. vivax, and P. falciparum as comparison.,We performed cloud and local computing to extract parasite transcriptomes from publicly available raw data of human blood samples.,We developed a Poisson Modelling (PM) method to confidently identify parasite derived transcripts in mixed RNAseq signals of infected host tissues.,We successfully retrieved and reconstructed parasite transcriptomes from infected patient blood as early as the first blood stage cycle; and the same methodology did not recover any significant signal from controls.,Surprisingly, these first generation blood parasites already show strong signature of transmission, which indicates the commitment from asexual-to-sexual stages.,Further, we place the results within the context of P. vivax’s complex life cycle, by developing mathematical models for P. vivax and P. falciparum and using sensitivity analysis assess the relative epidemiological impact of possible early stage transmission.,The study uncovers the earliest onset of P. vivax blood pathogenesis and highlights the challenges of P. vivax eradication programs.,The online version of this article (10.1186/s12918-018-0669-4) contains supplementary material, which is available to authorized users.

Limited data is available on feline leishmaniosis (FeL) caused by Leishmania infantum worldwide.,The LeishVet group presents in this report a review of the current knowledge on FeL, the epidemiological role of the cat in L. infantum infection, clinical manifestations, and recommendations on diagnosis, treatment and monitoring, prognosis and prevention of infection, in order to standardize the management of this disease in cats.,The consensus of opinions and recommendations was formulated by combining a comprehensive review of evidence-based studies and case reports, clinical experience and critical consensus discussions.,While subclinical feline infections are common in areas endemic for canine leishmaniosis, clinical illness due to L. infantum in cats is rare.,The prevalence rates of feline infection with L. infantum in serological or molecular-based surveys range from 0 % to more than 60 %.,Cats are able to infect sand flies and, therefore, they may act as a secondary reservoir, with dogs being the primary natural reservoir.,The most common clinical signs and clinicopathological abnormalities compatible with FeL include lymph node enlargement and skin lesions such as ulcerative, exfoliative, crusting or nodular dermatitis (mainly on the head or distal limbs), ocular lesions (mainly uveitis), feline chronic gingivostomatitis syndrome, mucocutaneous ulcerative or nodular lesions, hypergammaglobulinaemia and mild normocytic normochromic anaemia.,Clinical illness is frequently associated with impaired immunocompetence, as in case of retroviral coinfections or immunosuppressive therapy.,Diagnosis is based on serology, polymerase chain reaction (PCR), cytology, histology, immunohistochemistry (IHC) or culture.,If serological testing is negative or low positive in a cat with clinical signs compatible with FeL, the diagnosis of leishmaniosis should not be excluded and additional diagnostic methods (cytology, histology with IHC, PCR, culture) should be employed.,The most common treatment used is allopurinol.,Meglumine antimoniate has been administered in very few reported cases.,Both drugs are administered alone and most cats recover clinically after therapy.,Follow-up of treated cats with routine laboratory tests, serology and PCR is essential for prevention of clinical relapses.,Specific preventative measures for this infection in cats are currently not available.

In recent years, several clinical cases and epidemiological studies of feline vector-borne diseases (FVBD) have been reported worldwide.,Nonetheless, information on FVBD agents and their prevalence in Portugal is scarce.,Three-hundred and twenty domestic cats presented to 30 veterinary medical centres in the north and centre regions of Portugal were randomly sampled.,Blood was assayed by real-time polymerase chain reaction (PCR) for genera Anaplasma/Ehrlichia, genus Babesia, Hepatozoon canis, Hepatozoon felis, Leishmania infantum and the genus Rickettsia.,Babesia-positive samples were further tested for Babesia canis and Babesia vogeli.,Eighty (25.0%) out of the 320 cats were positive to at least one vector-borne agent, including seven (2.2%) cats co-infected with two agents.,Two cats (0.6%) were infected with Anaplasma/Ehrlichia spp., four (1.3%) with B. canis, 26 (8.1%) with B. vogeli, 50 (15.6%) with H. felis, one (0.3%) with L. infantum and four (1.3%) with Rickettsia spp.,No cat tested positive for H. canis.,One cat (0.3%) was co-infected with B. canis and B. vogeli, three (0.9%) with B. vogeli and H. felis, one (0.3%) with H. felis and L. infantum, and two (0.6%) with H. felis and Rickettsia spp.,A considerable prevalence of infection with vector-borne pathogens among the domestic feline population of the north and centre of Portugal has been revealed by the present study.,Additionally, this is the first detection of B. vogeli in cats from Europe and of H. felis in cats from Portugal.

Over the past 50 years, Plasmodium falciparum has developed resistance against all antimalarial drugs used against it: chloroquine, sulphadoxine-pyrimethamine, quinine, piperaquine and mefloquine.,More recently, resistance to the artemisinin derivatives and the resulting failure of artemisinin‐based combination therapy (ACT) are threatening all major gains made in malaria control.,Each time resistance has developed progressively, with delayed clearance of parasites first emerging only in a few regions, increasing in prevalence and geographic range, and then ultimately resulting in the complete failure of that antimalarial.,Drawing from this repeated historical chain of events, this article presents context‐specific approaches for combating drug‐resistant P. falciparum malaria.,The approaches begin with a context of drug‐sensitive parasites and focus on the prevention of the emergence of drug resistance.,Next, the approaches address a scenario in which resistance has emerged and is increasing in prevalence and geographic extent, with interventions focused on disrupting transmission through vector control, early diagnosis and treatment, and the use of new combination therapies.,Elimination is also presented as an approach for addressing the imminent failure of all available antimalarials.,The final drug resistance context presented is one in which all available antimalarials have failed; leaving only personal protection and the use of new antimalarials (or new combinations of antimalarials) as a viable strategy for dealing with complete resistance.,All effective strategies and contexts require a multipronged, holistic approach.

Gliding motility in Plasmodium parasites, the aetiological agents of malaria disease, is mediated by an actomyosin motor anchored in the outer pellicle of the motile cell.,Effective motility is dependent on a parasite myosin motor and turnover of dynamic parasite actin filaments.,To date, however, the basis for directional motility is not known.,Whilst myosin is very likely orientated as a result of its anchorage within the parasite, how actin filaments are orientated to facilitate directional force generation remains unexplained.,In addition, recent evidence has questioned the linkage between actin filaments and secreted surface antigens leaving the way by which motor force is transmitted to the extracellular milieu unknown.,Malaria parasites possess a markedly reduced repertoire of actin regulators, among which few are predicted to interact with filamentous (F)-actin directly.,One of these, PF3D7_1251200, shows strong homology to the coronin family of actin-filament binding proteins, herein referred to as PfCoronin.,Here the N terminal beta propeller domain of PfCoronin (PfCor-N) was expressed to assess its ability to bind and bundle pre-formed actin filaments by sedimentation assay, total internal reflection fluorescence (TIRF) microscopy and confocal imaging as well as to explore its ability to bind phospholipids.,In parallel a tagged PfCoronin line in Plasmodium falciparum was generated to determine the cellular localization of the protein during asexual parasite development and blood-stage merozoite invasion.,A combination of biochemical approaches demonstrated that the N-terminal beta-propeller domain of PfCoronin is capable of binding F-actin and facilitating formation of parallel filament bundles.,In parasites, PfCoronin is expressed late in the asexual lifecycle and localizes to the pellicle region of invasive merozoites before and during erythrocyte entry.,PfCoronin also associates strongly with membranes within the cell, likely mediated by interactions with phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) at the plasma membrane.,These data suggest PfCoronin may fulfil a key role as the critical determinant of actin filament organization in the Plasmodium cell.,This raises the possibility that macro-molecular organization of actin mediates directional motility in gliding parasites.,The online version of this article (doi:10.1186/s12936-015-0801-5) contains supplementary material, which is available to authorized users.

The role played by different mammal species in the maintenance of Trypanosoma cruzi is not constant and varies in time and place.,This study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of T. cruzi in Tauá, state of Ceará, Caatinga area, Brazil, with an emphasis on those environments colonised by Triatoma brasiliensis.,Direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and outdoor mammals and multiplex polymerase chain reaction was used on wild mammals.,Cytochrome b was used as a food source for wild insects.,The serum prevalence in dogs was 38% (20/53), while in pigs it was 6% (2/34).,The percentages of the most abundantly infected wild animals were as follows: Thrichomys laurentius 74% (83/112) and Kerodon rupestris 10% (11/112).,Of the 749 triatomines collected in the household research, 49.3% (369/749) were positive for T. brasiliensis, while 6.8% were infected with T. cruzi (25/369).,In captured animals, T. brasiliensis shares a natural environment with T. laurentius, K. rupestris, Didelphis albiventris, Monodelphis domestica, Galea spixii, Wiedomys pyrrhorhinos, Conepatus semistriatus and Mus musculus.,In animals identified via their food source, T. brasiliensis shares a natural environment with G. spixii, K. rupestris, Capra hircus, Gallus gallus, Tropidurus oreadicus and Tupinambis merianae.,The high prevalence of T. cruzi in household and peridomiciliar animals reinforces the narrow relationship between the enzootic cycle and humans in environments with T. brasiliensis and characterises it as ubiquitous.

Interruption of vector-borne transmission of Trypanosoma cruzi remains an unrealized objective in many Latin American countries.,The task of vector control is complicated by the emergence of vector insects in urban areas.,Utilizing data from a large-scale vector control program in Arequipa, Peru, we explored the spatial patterns of infestation by Triatoma infestans in an urban and peri-urban landscape.,Multilevel logistic regression was utilized to assess the associations between household infestation and household- and locality-level socio-environmental measures.,Of 37,229 households inspected for infestation, 6,982 (18.8%; 95% CI: 18.4 - 19.2%) were infested by T. infestans.,Eighty clusters of infestation were identified, ranging in area from 0.1 to 68.7 hectares and containing as few as one and as many as 1,139 infested households.,Spatial dependence between infested households was significant at distances up to 2,000 meters.,Household T. infestans infestation was associated with household- and locality-level factors, including housing density, elevation, land surface temperature, and locality type.,High levels of T. infestans infestation, characterized by spatial heterogeneity, were found across extensive urban and peri-urban areas prior to vector control.,Several environmental and social factors, which may directly or indirectly influence the biology and behavior of T. infestans, were associated with infestation.,Spatial clustering of infestation in the urban context may both challenge and inform surveillance and control of vector reemergence after insecticide intervention.

Proteins Pfs230 and Pfs48/45 are Plasmodium falciparum transmission-blocking (TB) vaccine candidates that form a membrane-bound protein complex on gametes.,The biological role of Pfs230 or the Pfs230-Pfs48/45 complex remains poorly understood.,Here, we present the crystal structure of recombinant Pfs230 domain 1 (Pfs230D1M), a 6-cysteine domain, in complex with the Fab fragment of a TB monoclonal antibody (mAb) 4F12.,We observed the arrangement of Pfs230 on the surface of macrogametes differed from that on microgametes, and that Pfs230, with no known membrane anchor, may exist on the membrane surface in the absence of Pfs48/45.,4F12 appears to sterically interfere with Pfs230 function.,Combining mAbs against different epitopes of Pfs230D1 or of Pfs230D1 and Pfs48/45, significantly increased TB activity.,These studies elucidate a mechanism of action of the Pfs230D1 vaccine, model the functional activity induced by a polyclonal antibody response and support the development of TB vaccines targeting Pfs230D1 and Pfs230D1-Pfs48/45.,With the aim to advance the development of a P. falciparum transmission blocking vaccine, Singh et al. determine the crystal structure of Pfs230D1 in complex with the Fab fragment of TB mAb 4F12.,They further study the cellular localization of Pfs230 on the surface of sexual stages of parasites and the effect of combining TB mAbs against Pfs230 and Pfs48/45.

Mosquito-based malaria transmission-blocking vaccines (mTBVs) target midgut-surface antigens of the Plasmodium parasite's obligate vector, the Anopheles mosquito.,The alanyl aminopeptidase N (AnAPN1) is the leading mTBV immunogen; however AnAPN1's role in Plasmodium infection of the mosquito and how anti-AnAPN1 antibodies functionally block parasite transmission remains elusive.,Here we present the 2.65 Å crystal structure of AnAPN1 and the immunoreactivity and transmission-blocking profile of three AnAPN1 monoclonal antibodies (mAb), including mAb 4H5B7, which effectively block transmission of natural strains of Plasmodium falciparum.,Utilizing the AnAPN1 structure we map the conformation-dependent 4H5B7 neo-epitope to a previously uncharacterized region on domain 1, and further demonstrate that non-human primate neo-epitope-specific IgG also block parasite transmission.,We discuss the prospect of a novel biological function of AnAPN1 as a receptor for Plasmodium in the mosquito midgut and the implications for redesigning the AnAPN1 mTBV.

A very large biomass of intact asexual-stage malaria parasites accumulates in the spleen of asymptomatic human individuals infected with Plasmodium vivax.,The mechanisms underlying this intense tropism are not clear.,We hypothesised that immature reticulocytes, in which P. vivax develops, may display high densities in the spleen, thereby providing a niche for parasite survival.,We examined spleen tissue in 22 mostly untreated individuals naturally exposed to P. vivax and Plasmodium falciparum undergoing splenectomy for any clinical indication in malaria-endemic Papua, Indonesia (2015 to 2017).,Infection, parasite and immature reticulocyte density, and splenic distribution were analysed by optical microscopy, flow cytometry, and molecular assays.,Nine non-endemic control spleens from individuals undergoing spleno-pancreatectomy in France (2017 to 2020) were also examined for reticulocyte densities.,There were no exclusion criteria or sample size considerations in both patient cohorts for this demanding approach.,In Indonesia, 95.5% (21/22) of splenectomy patients had asymptomatic splenic Plasmodium infection (7 P. vivax, 13 P. falciparum, and 1 mixed infection).,Significant splenic accumulation of immature CD71 intermediate- and high-expressing reticulocytes was seen, with concentrations 11 times greater than in peripheral blood.,Accordingly, in France, reticulocyte concentrations in the splenic effluent were higher than in peripheral blood.,Greater rigidity of reticulocytes in splenic than in peripheral blood, and their higher densities in splenic cords both suggest a mechanical retention process.,Asexual-stage P. vivax-infected erythrocytes of all developmental stages accumulated in the spleen, with non-phagocytosed parasite densities 3,590 times (IQR: 2,600 to 4,130) higher than in circulating blood, and median total splenic parasite loads 81 (IQR: 14 to 205) times greater, accounting for 98.7% (IQR: 95.1% to 98.9%) of the estimated total-body P. vivax biomass.,More reticulocytes were in contact with sinus lumen endothelial cells in P. vivax- than in P. falciparum-infected spleens.,Histological analyses revealed 96% of P. vivax rings/trophozoites and 46% of schizonts colocalised with 92% of immature reticulocytes in the cords and sinus lumens of the red pulp.,Larger splenic cohort studies and similar investigations in untreated symptomatic malaria are warranted.,Immature CD71+ reticulocytes and splenic P. vivax-infected erythrocytes of all asexual stages accumulate in the same splenic compartments, suggesting the existence of a cryptic endosplenic lifecycle in chronic P. vivax infection.,Findings provide insight into P. vivax-specific adaptions that have evolved to maximise survival and replication in the spleen.,Dr.,Anstey and co-authors found that P. vivax-infected immature reticulocytes and erythrocytes accumulate in the same splenic compartments, suggesting existence of a cryptic endosplenic lifecycle in chronic P. vivax infection that maximizes survival and replication in the spleen.

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency overlaps with malaria endemicity although it predisposes carriers to hemolysis.,This fact supports the protection hypothesis against malaria.,The aim of this systematic review is to assess the presence and the extent of protective association between G6PD deficiency and malaria.,Thirteen databases were searched for papers reporting any G6PD alteration in malaria patients.,Twenty-eight of the included 30 studies were eligible for the meta-analysis.,Results showed absence of negative association between G6PD deficiency and uncomplicated falciparum malaria (odds ratio (OR), 0.77; 95% confidence interval (CI), 0.59-1.02; p = 0.07).,However, this negative association happened in Africa (OR, 0.59; 95% CI, 0.40-0.86; p = 0.007) but not in Asia (OR, 1.24; 95% CI, 0.96-1.61; p = 0.10), and in the heterozygotes (OR, 0.70; 95% CI, 0.57-0.87; p = 0.001) but not the homo/hemizygous (OR, 0.70; 95% CI, 0.46-1.07; p = 0.10).,There was no association between G6PD deficiency and total severe malaria (OR, 0.82; 95% CI, 0.61-1.11; p = 0.20).,Similarly, there was no association with other malaria species.,G6PD deficiency can potentially protect against uncomplicated malaria in African countries, but not severe malaria.,Interestingly, this protection was mainly in heterozygous, being x-linked thus related to gender.

In India, visceral leishmaniasis (VL) caused by Leishmania donovani has been successfully treated with miltefosine with a cure rate of > 90%.,To assess the efficacy and safety of oral miltefosine against Brazilian VL, which is caused by Leishmania infantum, a phase II, open-label, dose-escalation study of oral miltefosine was conducted in children (aged 2-12 years) and adolescent-adults (aged 13-60 years).,Definitive cure was assessed at a 6-month follow-up visit.,The cure rate was only 42% (6 of 14 patients) with a recommended treatment of 28 days and 68% (19 of 28 patients) with an extended treatment of 42 days.,The in vitro miltefosine susceptibility profile of intracellular amastigote stages of the pretreatment isolates, from cured and relapsed patients, showed a positive correlation with the clinical outcome.,The IC50 mean (SEM) of eventual cures was 5.1 (0.4) µM, whereas that of eventual failures was 12.8 (1.9) µM (P = 0.0002).,An IC50 above 8.0 µM predicts failure with 82% sensitivity and 100% specificity.,The finding of L. infantum amastigotes resistant to miltefosine in isolates from patients who eventually failed treatment strongly suggests natural resistance to this drug, as miltefosine had never been used in Brazil before this trial was carried out.

Visceral Leishmaniasis (VL) is an important protozoan opportunistic disease in HIV patients in endemic areas.,East Africa is second to the Indian subcontinent in the global VL caseload and first in VL-HIV coinfection rate.,Because of the alteration in the disease course, the diagnostic challenges, and the poor treatment responses, VL with HIV coinfection has become a very serious challenge in East Africa today.,Field experience with the use of liposomal amphotericin B in combination with miltefosine, followed by secondary prophylaxis and antiretroviral drugs, looks promising.,However, this needs to be confirmed through clinical trials.,Better diagnostic and follow-up methods for relapse and prediction of relapse should also be looked for.,Basic research to understand the immunological interaction of the two infections may ultimately help to improve the management of the coinfection.

Infection with Plasmodium can elicit antibodies that inhibit parasite survival in the mosquito, when they are ingested in an infectious blood meal.,Here, we determine the transmission-reducing activity (TRA) of naturally acquired antibodies from 648 malaria-exposed individuals using lab-based mosquito-feeding assays.,Transmission inhibition is significantly associated with antibody responses to Pfs48/45, Pfs230, and to 43 novel gametocyte proteins assessed by protein microarray.,In field-based mosquito-feeding assays the likelihood and rate of mosquito infection are significantly lower for individuals reactive to Pfs48/45, Pfs230 or to combinations of the novel TRA-associated proteins.,We also show that naturally acquired purified antibodies against key transmission-blocking epitopes of Pfs48/45 and Pfs230 are mechanistically involved in TRA, whereas sera depleted of these antibodies retain high-level, complement-independent TRA.,Our analysis demonstrates that host antibody responses to gametocyte proteins are associated with reduced malaria transmission efficiency from humans to mosquitoes.,Naturally acquired antibodies may inhibit Plasmodium survival in mosquitoes, alter malaria transmission dynamics, and form the basis for transmission-blocking vaccines.,Here, using sera from malaria-exposed individuals, Stone et al. reveal novel antibody correlates of transmission-reducing activity.

Complete sterile protection to Plasmodium falciparum (Pf) infection mediated by pre-erythrocytic immunity can be experimentally induced under chloroquine prophylaxis, through immunization with sporozoites from infected mosquitoes' bites (CPS protocol).,To characterize the profile of CPS induced antibody (Ab) responses, we developed a proteome microarray containing 809 Pf antigens showing a distinct Ab profile with recognition of antigens expressed in pre-erythrocytic life-cycle stages.,In contrast, plasma from naturally exposed semi-immune individuals from Kenya was skewed toward antibody reactivity against asexual blood stage antigens.,CPS-immunized and semi-immune individuals generated antibodies against 192 and 202 Pf antigens, respectively, but only 60 antigens overlapped between the two groups.,Although the number of reactive antigens varied between the CPS-immunized individuals, all volunteers reacted strongly against the pre-erythrocytic antigens circumsporozoite protein (CSP) and liver stage antigen 1 (LSA1).,Well classified merozoite and erythrocytic antigens were strongly reactive in semi-immune individuals but lacking in the CPS immunized group.,These data show that the antibody profile of CPS-immunized and semi-immune groups have quite distinct profiles reflecting their protective immunity; antibodies from CPS immunized individuals react strongly against pre-erythrocytic while semi-immune individuals mainly react against erythrocytic antigens.

The current epidemic of artemisinin resistant Plasmodium falciparum in Southeast Asia is the result of a soft selective sweep involving at least 20 independent kelch13 mutations.,In a large global survey, we find that kelch13 mutations which cause resistance in Southeast Asia are present at low frequency in Africa.,We show that African kelch13 mutations have originated locally, and that kelch13 shows a normal variation pattern relative to other genes in Africa, whereas in Southeast Asia there is a great excess of non-synonymous mutations, many of which cause radical amino-acid changes.,Thus, kelch13 is not currently undergoing strong selection in Africa, despite a deep reservoir of variations that could potentially allow resistance to emerge rapidly.,The practical implications are that public health surveillance for artemisinin resistance should not rely on kelch13 data alone, and interventions to prevent resistance must account for local evolutionary conditions, shown by genomic epidemiology to differ greatly between geographical regions.,DOI:http://dx.doi.org/10.7554/eLife.08714.001,Malaria is an infectious disease caused by a microscopic parasite called Plasmodium, which is transferred between humans by mosquitos.,One species of malaria parasite called Plasmodium falciparum can cause particularly severe and life-threatening forms of the disease.,Currently, the most widely used treatment for P. falciparum infections is artemisinin combination therapy, a treatment that combines the drug artemisinin (or a closely related molecule) with another antimalarial drug.,However, resistance to artemisinin has started to spread throughout Southeast Asia.,Artemisinin resistance is caused by mutations in a parasite gene called kelch13, and researchers have identified over 20 different mutations in P. falciparum that confer artemisinin resistance.,The diversity of mutations involved, and the fact that the same mutation can arise independently in different locations, make it difficult to track the spread of resistance using conventional molecular marker approaches.,Here, Amato, Miotto et al. sequenced the entire genomes of more than 3,000 clinical samples of P. falciparum from Southeast Asia and Africa, collected as part of a global network of research groups called the MalariaGEN Plasmodium falciparum Community Project.,Amato, Miotto et al. found that African parasites had independently acquired many of the same kelch13 mutations that are known to cause resistance to artemisinin in Southeast Asia.,However the kelch13 mutations seen in Africa remained at low levels in the parasite population, and appeared to be under much less pressure for evolutionary selection than those found in Southeast Asia.,These findings demonstrate that the emergence and spread of resistance to antimalarial drugs does not depend solely on the mutational process, but also on other factors that influence whether the mutations will spread in the population.,Understanding how this is affected by different patterns of drug treatments and other environmental conditions will be important in developing more effective strategies for combating malaria.,DOI:http://dx.doi.org/10.7554/eLife.08714.002

The emergence of artemisinin resistance has raised concerns that the most potent antimalarial drug may be under threat.,The currently recommended daily dose of artesunate (AS) is 4 mg/kg, and is administered for 3 days together with a partner antimalarial drug.,This study investigated the impact of different AS doses on clinical and parasitological responses in malaria patients from an area of known artemisinin resistance in western Cambodia.,Adult patients with uncomplicated P. falciparum malaria were randomized into one of three 7-day AS monotherapy regimens: 2, 4 or 6 mg/kg/day (total dose 14, 28 and 42 mg/kg).,Clinical, parasitological, pharmacokinetic and in vitro drug sensitivity data was collected over a 7-day inpatient period and during weekly follow-up to 42 days.,143 patients were enrolled (n = 75, 40 and 28 to receive AS 2, 4 and 6 mg/kg/day respectively).,Cure rates were high in all treatment groups at 42 days despite almost half the patients remaining parasitemic on Day 3.,There was no impact of increasing AS dose on median parasite clearance times, median parasite clearance rates or on the proportion of patients remaining parasitemic on Day 3.,However at the lowest dose used (2 mg/kg/d) patients with parasitemia >10,000/µL had longer median (IQR) parasite clearance times than those with parasitemia <10,000/µL (63 (48-75) vs. 84 (66-96) hours, p<0.0001). 19% of patients in the high-dose arm developed neutropenia (absolute neutrophil count <1.0×109/L) by Day 14 and resulted in the arm being halted early.,There is no pharmacodynamic benefit of increasing the daily dose of AS (4mg/kg) currently recommended for short-course combination treatment of uncomplicated malaria, even in regions with emerging artemisinin resistance, as long as the partner drug retains high efficacy.,ClinicalTrials.gov NCT00722150.

The first line treatment for uncomplicated falciparum malaria is artemisinin-based combination therapy (ACT), which consists of an artemisinin derivative coadministered with a longer-acting partner drug.,However, the spread of Plasmodium falciparum resistant to both artemisinin and its partner drugs poses a major global threat to malaria control activities.,The first line treatment for uncomplicated falciparum malaria is artemisinin-based combination therapy (ACT), which consists of an artemisinin derivative coadministered with a longer-acting partner drug.,However, the spread of Plasmodium falciparum resistant to both artemisinin and its partner drugs poses a major global threat to malaria control activities.,Novel strategies are needed to retard and reverse the spread of these resistant parasites.,One such strategy is triple artemisinin-based combination therapy (TACT).,We developed a mechanistic within-host mathematical model to investigate the efficacy of a TACT (dihydroartemisinin-piperaquine-mefloquine [DHA-PPQ-MQ]) for use in South-East Asia, where DHA and PPQ resistance are now increasingly prevalent.,Comprehensive model simulations were used to explore the degree to which the underlying resistance influences the parasitological outcomes.,The effect of MQ dosing on the efficacy of TACT was quantified at various degrees of DHA and PPQ resistance.,To incorporate interactions between drugs, a novel model is presented for the combined effect of DHA-PPQ-MQ, which illustrates how the interactions can influence treatment efficacy.,When combined with a standard regimen of DHA and PPQ, the administration of three 6.7-mg/kg doses of MQ was sufficient to achieve parasitological efficacy greater than that currently recommended by World Health Organization (WHO) guidelines.,As a result, three 8.3-mg/kg doses of MQ, the current WHO-recommended dosing regimen for MQ, combined with DHA-PPQ, has the potential to produce high cure rates in regions where resistance to DHA-PPQ has emerged.

Antimalarial chemotherapy, globally reliant on artemisinin-based combination therapies (ACTs), is threatened by the spread of drug resistance in Plasmodium falciparum parasites.,Here we use zinc-finger nucleases to genetically modify the multidrug resistance-1 transporter PfMDR1 at amino acids 86 and 184, and demonstrate that the widely prevalent N86Y mutation augments resistance to the ACT partner drug amodiaquine and the former first-line agent chloroquine.,In contrast, N86Y increases parasite susceptibility to the partner drugs lumefantrine and mefloquine, and the active artemisinin metabolite dihydroartemisinin.,The PfMDR1 N86 plus Y184F isoform moderately reduces piperaquine potency in strains expressing an Asian/African variant of the chloroquine resistance transporter PfCRT.,Mutations in both digestive vacuole-resident transporters are thought to differentially regulate ACT drug interactions with host haem, a product of parasite-mediated haemoglobin degradation.,Global mapping of these mutations illustrates where the different ACTs could be selectively deployed to optimize treatment based on regional differences in PfMDR1 haplotypes.,Antimalarial chemotherapy relies on combination therapies (ACTs) consisting of an artemisinin derivative and a partner drug.,Here, the authors study the effects of globally prevalent mutations in a multidrug resistance transporter (PfMDR1) on the parasite's susceptibility to ACT drugs.

Toxoplasma gondii infects up to one third of the world's population.,A key to the success of T. gondii as a parasite is its ability to persist for the life of its host as bradyzoites within tissue cysts.,The glycosylated cyst wall is the key structural feature that facilitates persistence and oral transmission of this parasite.,Because most of the antibodies and reagents that recognize the cyst wall recognize carbohydrates, identification of the components of the cyst wall has been technically challenging.,We have identified CST1 (TGME49_064660) as a 250 kDa SRS (SAG1 related sequence) domain protein with a large mucin-like domain.,CST1 is responsible for the Dolichos biflorus Agglutinin (DBA) lectin binding characteristic of T. gondii cysts.,Deletion of CST1 results in reduced cyst number and a fragile brain cyst phenotype characterized by a thinning and disruption of the underlying region of the cyst wall.,These defects are reversed by complementation of CST1.,Additional complementation experiments demonstrate that the CST1-mucin domain is necessary for the formation of a normal cyst wall structure, the ability of the cyst to resist mechanical stress, and binding of DBA to the cyst wall.,RNA-seq transcriptome analysis demonstrated dysregulation of bradyzoite genes within the various cst1 mutants.,These results indicate that CST1 functions as a key structural component that confers essential sturdiness to the T. gondii tissue cyst critical for persistence of bradyzoite forms.

In RNA silencing, small RNAs produced by the RNase-III Dicer guide Argonaute-like proteins as part of RNA-induced silencing complexes (RISC) to regulate gene expression transcriptionally or post-transcriptionally.,Here, we have characterized the RNA silencing machinery and exhaustive small RNAome of Toxoplasma gondii, member of the Apicomplexa, a phylum of animal- and human-infecting parasites that cause extensive health and economic damages to human populations worldwide.,Remarkably, the small RNA-generating machinery of Toxoplasma is phylogenetically and functionally related to that of plants and fungi, and accounts for an exceptionally diverse array of small RNAs.,This array includes conspicuous populations of repeat-associated small interfering RNA (siRNA), which, as in plants, likely generate and maintain heterochromatin at DNA repeats and satellites.,Toxoplasma small RNAs also include many microRNAs with clear metazoan-like features whose accumulation is sometimes extremely high and dynamic, an unexpected finding given that Toxoplasma is a unicellular protist.,Both plant-like heterochromatic small RNAs and metazoan-like microRNAs bind to a single Argonaute protein, Tg-AGO.,Toxoplasma miRNAs co-sediment with polyribosomes, and thus, are likely to act as translational regulators, consistent with the lack of catalytic residues in Tg-AGO.,Mass spectrometric analyses of the Tg-AGO protein complex revealed a common set of virtually all known RISC components so far characterized in human and Drosophila, as well as novel proteins involved in RNA metabolism.,In agreement with its loading with heterochromatic small RNAs, Tg-AGO also associates substoichiometrically with components of known chromatin-repressing complexes.,Thus, a puzzling patchwork of silencing processor and effector proteins from plant, fungal and metazoan origin accounts for the production and action of an unsuspected variety of small RNAs in the single-cell parasite Toxoplasma and possibly in other apicomplexans.,This study establishes Toxoplasma as a unique model system for studying the evolution and molecular mechanisms of RNA silencing among eukaryotes.

Malaria transmission is influenced by climate, land use and deliberate intervention.,Recent declines have been observed in malaria transmission.,Here, we show that the continent has witnessed a long-term recession in the prevalence of Plasmodium falciparum since 1900-29 (40%) to 2010-15 (24%), interrupted at different times by periods of rapidly increasing and decreasing transmission.,The cycles and trend over the last 115 years are inconsistent with simplistic explanations in terms of climate or intervention alone.,Previous global initiatives had minor impacts on malaria transmission, and a historically unprecedented decline has been observed since 2000.,However, there has been little change to the continued high transmission belt covering large parts of West and Central Africa.,Previous efforts to model the changing patterns of P. falciparum transmission intensity in Africa have been limited to the last 15 years1,2, or have used maps of historical expert opinion3.,We provide quantitative data comprising 50,424 surveys at 36,966 geocoded locations to cover 115 years of malaria history in sub-Saharan Africa.

In endemic areas, many people experience asymptomatic Plasmodium infections, particularly older children and adults, but their transmission contribution is unknown.,Though not the exclusive determinant of infectiousness, transmission from humans to mosquitoes requires blood meals containing gametocytes.,Gametocytes often occur at submicroscopic densities, challenging measurement in human populations.,More sensitive molecular techniques allow better characterization of gametocyte epidemiologic patterns.,Approximately 30 households were selected from each of eight sites in southern Malawi during two cross-sectional surveys.,Blood was sampled from 623 people during the dry season and 896 the following rainy season.,Among people PCR-positive for Plasmodium falciparum, mature gametocytes were detected by qRT-PCR.,Regression models evaluated predictors of gametocyte carriage and density in the total population and among those with PCR-positive infections.,The prevalence of gametocyte carriage by molecular testing was 3.5% during the dry season and 8.6% during the rainy season, and by microscopy 0.8 and 3.3%, respectively.,Nearly half of PCR-positive infections carried gametocytes, regardless of recent symptom status.,Among P. falciparum-infected people, only living in unfinished houses and age were significantly associated with gametocyte presence.,Infected people in unfinished houses had higher odds of carrying gametocytes (OR 2.24, 95% CI 1.16-4.31), and 31% (95% CI 3-65%) higher gametocyte density than those in finished houses.,School-age children (5-15 years), had higher odds than adults (≥16 years) of having gametocytes when infected (OR 2.77, 95% CI 1.47-5.19), but 31% (95% CI 11-47%) lower gametocyte density.,Children <5 years did not have significantly higher odds of gametocyte carriage or density when infected than adults.,School-age children frequently carry gametocytes in communities of southern Malawi and represent an under-recognized reservoir of infection.,Malaria elimination strategies should address these frequently asymptomatic reservoirs, especially in highly endemic areas.,Improved household construction may also reduce the infectious reservoir.,The online version of this article (doi:10.1186/s12936-016-1587-9) contains supplementary material, which is available to authorized users.

Pyrethroid resistance in malaria vector, An. funestus is increasingly reported across Africa, threatening the sustainability of pyrethroid-based control interventions, including long lasting insecticidal nets (LLINs).,Managing this problem requires understanding of the molecular basis of the resistance from different regions of the continent, to establish whether it is being driven by a single or independent selective events.,Here, using a genome-wide transcription profiling of pyrethroid resistant populations from southern (Malawi), East (Uganda), and West Africa (Benin), we investigated the molecular basis of resistance, revealing strong differences between the different African regions.,The duplicated cytochrome P450 genes (CYP6P9a and CYP6P9b) which were highly overexpressed in southern Africa are not the most upregulated in other regions, where other genes are more overexpressed, including GSTe2 in West (Benin) and CYP9K1 in East (Uganda).,The lack of directional selection on both CYP6P9a and CYP6P9b in Uganda in contrast to southern Africa further supports the limited role of these genes outside southern Africa.,However, other genes such as the P450 CYP9J11 are commonly overexpressed in all countries across Africa.,Here, CYP9J11 is functionally characterized and shown to confer resistance to pyrethroids and moderate cross-resistance to carbamates (bendiocarb).,The consistent overexpression of GSTe2 in Benin is coupled with a role of allelic variation at this gene as GAL4-UAS transgenic expression in Drosophila flies showed that the resistant 119F allele is highly efficient in conferring both DDT and permethrin resistance than the L119.,The heterogeneity in the molecular basis of resistance and cross-resistance to insecticides in An. funestus populations throughout sub-Saharan African should be taken into account in designing resistance management strategies.

Understanding the dynamics of insecticide resistance in African malaria vectors is crucial for successful implementation of resistance management strategies in the continent.,This study reports a high and multiple insecticide resistance in Anopheles funestus from southern Ghana which could compromise the Malaria Operational Plan in this country, if not tackled.,Adult Anopheles mosquitoes were collected in Obuasi and Adawukwa, in southern Ghana.,Plasmodium infection rates, susceptibility to the main insecticides used in public health and the molecular basis of insecticide resistance were established.,An. funestus (sensu stricto) (s.s.) was the predominant mosquito species found resting inside the houses in Obuasi, while at Adawukwa it was found together with An. coluzzii.,Parasite rates were high in An. funestus (s.s.) populations from both localities, with Plasmodium infection rates greater than 12.5 %.,Both, An. funestus (s.s.) and An. coluzzii, from the two sites exhibited high resistance to the insecticide from various classes including the pyrethroids, carbamates and DDT, but remained fully susceptible to the organophosphates.,A preliminary characterization of the underlying molecular mechanisms of resistance in An. funestus (s.s.) populations from both sites revealed that CYP6P9a, CYP6P9b, CYP6M7 and GSTe2 genes are upregulated, markedly higher in Obuasi (between 3.35 and 1.83 times) than in Adawukwa population.,The frequency of L119F-GSTe2 and A296S-RDL resistance markers were also higher in Obuasi (42.5 and 68.95 % higher), compared with An. funestus (s.s.) populations from Adawukwa.,These findings suggest that the similar resistance pattern observed in both An. funestus (s.s.) populations are driven by different mechanisms.,Resistance to multiple insecticides in public health use is present in malaria vectors from Ghana with major resistance genes already operating in the field.,This should be taken into consideration in the design of resistance management strategies to avoid operational failure.

We detected 2 natural, asymptomatic Plasmodium inui monoinfections in humans in Malaysia by using nested PCR on concentrated high-volume blood samples.,We found a P. inui-positive Anopheles cracens mosquito in the same site as the human infections.,Investigators should use ultrasensitive detection methods to identify simian malaria parasite transmission in humans.

Plasmodium knowlesi is a significant cause of human malaria in Sarawak, Malaysian Borneo.,Only one study has been previously undertaken in Sarawak to identify vectors of P. knowlesi, where Anopheles latens was incriminated as the vector in Kapit, central Sarawak.,A study was therefore undertaken to identify malaria vectors in a different location in Sarawak.,Mosquitoes found landing on humans and resting on leaves over a 5-day period at two sites in the Lawas District of northern Sarawak were collected and identified.,DNA samples extracted from salivary glands of Anopheles mosquitoes were subjected to nested PCR malaria-detection assays.,The small subunit ribosomal RNA (SSU rRNA) gene of Plasmodium was sequenced, and the internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of the mosquitoes were sequenced from the Plasmodium-positive samples for phylogenetic analysis.,Totals of 65 anophelines and 127 culicines were collected.,By PCR, 6 An. balabacensis and 5 An. donaldi were found to have single P. knowlesi infections while 3 other An. balabacensis had either single, double or triple infections with P. inui, P. fieldi, P. cynomolgi and P. knowlesi.,Phylogenetic analysis of the Plasmodium SSU rRNA gene confirmed 3 An. donaldi and 3 An. balabacensis with single P. knowlesi infections, while 3 other An. balabacensis had two or more Plasmodium species of P. inui, P. knowlesi, P. cynomolgi and some species of Plasmodium that could not be conclusively identified.,Phylogenies inferred from the ITS2 and/or cox1 sequences of An. balabacensis and An. donaldi indicate that they are genetically indistinguishable from An. balabacensis and An. donaldi, respectively, found in Sabah, Malaysian Borneo.,Previously An. latens was identified as the vector for P. knowlesi in Kapit, central Sarawak, Malaysian Borneo, and now An. balabacensis and An. donaldi have been incriminated as vectors for zoonotic malaria in Lawas, northern Sarawak.

Congenital infection with Trypanosoma cruzi is a global problem, occurring on average in 5% of children born from chronically infected mothers in endemic areas, with variations depending on the region.,This presentation aims to focus on and update epidemiological data, research methods, involved factors, control strategy and possible prevention of congenital infection with T. cruzi.,Considering that etiological treatment of the child is always effective if performed before one year of age, the diagnosis of infection in pregnant women and their newborns has to become the standard of care and integrated into the surveillance programs of syphilis and human immunodeficiency virus.,In addition to the standard tests, polymerase chain reaction performed on blood of neonates of infected mothers one month after birth might improve the diagnosis of congenital infection.,Recent data bring out that its transmission can be prevented through treatment of infected women before they become pregnant.,The role of parasite genotypes and host genetic factors in parasite transmission and development of infection in foetuses/neonates has to be more investigated in order to better estimate the risk factors and impact on health of congenital infection with T. cruzi.

Chagas disease is a tropical parasitic disease affecting about 10 million people, mostly in the Americas, and transmitted mainly by triatomine bugs.,Insect vector control with indoor residual insecticides and the promotion of housing improvement is the main control intervention.,The success of such interventions relies on their acceptance and appropriation by communities, which depends on their knowledge and perceptions of both the disease and the vector.,In this study, we investigated school-aged children's knowledge and perception on triatomine vectors and Chagas disease to further understand how communities view this vector and the disease in Yucatan, Mexico.,We performed an analysis of children's drawings on the theme of triatomines and their house in several rural villages, to explore in an open-ended manner their views, understanding and misconceptions.,A total of 261 drawings were collected from children ages 6-12 from four villages.,We found that children are very familiar with triatomine vectors, and know very well many aspects of their biology and ecology, and in particular their blood-feeding habits.,On the other hand, their drawings suggest that the role of triatomines as vectors of a chronic and severe cardiac disease is less understood, and the main perceived health threat appears limited to the bite itself, as previously observed in adults.,These results have important implications for the specific design of future education materials and campaigns, and for the promotion of the inclusion of children in raising Chagas disease awareness in these endemic communities.

In Plasmodium falciparum malaria, CD8+ T cells play a double-edged role.,Liver-stage specific CD8+ T cells can confer protection, as has been shown in several vaccine studies.,Blood-stage specific CD8+ T cells, on the other hand, contribute to the development of cerebral malaria in murine models of malaria.,The role of CD8+ T cells in humans during the blood-stage of P. falciparum remains unclear.,As part of a cross-sectional malaria study in Ghana, granzyme B levels and CD8+ T cells phenotypes were compared in the peripheral blood of children with complicated malaria, uncomplicated malaria, afebrile but asymptomatically infected children and non-infected children.,Granzyme B levels in the plasma were significantly higher in children with febrile malaria than in afebrile children.,CD8+ T cells were the main T cell subset expressing granzyme B.,The proportion of granzyme B+ CD8+ T cells was significantly higher in children with complicated malaria than in uncomplicated malaria, whereas the activation marker CD38 on CD8+ T cells showed similar expression levels.,This suggests a pathogenic role of cytotoxic CD8+ T cells in the development of malaria complications in humans.

Severe malaria (SM) is a major cause of death in sub-Saharan Africa.,Identification of both specific and sensitive clinical features to predict death is needed to improve clinical management.,A 13-year observational study was conducted from 1997 through 2009 of 2,901 children with SM enrolled at the Royal Victoria Teaching Hospital in The Gambia to identify sensitive and specific predictors of poor outcome in Gambian children with severe malaria between the ages 4 months to 14 years.,We have measured the sensitivity and specificity of clinical features that predict death or development of neurological sequelae.,Impaired consciousness (odds ratio {OR} 4.4 [95% confidence interval {CI}, 2.7-7.3]), respiratory distress (OR 2.4 [95%CI, 1.7-3.2]), hypoglycemia (OR 1.7 [95%CI, 1.2-2.3]), jaundice (OR 1.9 [95%CI, 1.2-2.9]) and renal failure (OR 11.1 [95%CI, 3.3-36.5]) were independently associated with death in children with SM.,The clinical features that showed the highest sensitivity and specificity to predict death were respiratory distress (area under the curve 0.63 [95%CI, 0.60-0.65]) and impaired consciousness (AUC 0.61[95%CI, 0.59-0.63]), which were comparable to the ability of hyperlactatemia (blood lactate>5 mM) to predict death (AUC 0.64 [95%CI, 0.55-0.72]).,A Blantyre coma score (BCS) of 2 or less had a sensitivity of 74% and specificity of 67% to predict death (AUC 0.70 [95% C.I.,0.68-0.72]), and sensitivity and specificity of 74% and 69%, respectively to predict development of neurological sequelae (AUC 0.72 [95% CI, 0.67-0.76]).,The specificity of this BCS threshold to identify children at risk of dying improved in children less than 3 years of age (AUC 0.74, [95% C.I 0.71-0.76]).,The BCS is a quantitative predictor of death.,A BCS of 2 or less is the most sensitive and specific clinical feature to predict death or development of neurological sequelae in children with SM.

Malaria is the most prevalent parasitic disease in the world.,In Brazil, the largest number of malaria cases (98%) is within the Legal Amazon region, where Plasmodium vivax is responsible for over 80% of diagnosed cases.,The aim of this study was to investigate the annexin-A1 expression in CD4+, CD8+ T cells, regulatory T cells (Treg) and cytokine IL-10 quantification in plasma from patients with malaria caused by P. vivax.,The quantification of the cytokine IL-10 of patients infected with P. vivax and healthy controls were evaluated by enzyme-linked immunosorbent assay (ELISA).,The determination of the expression of annexin-A1 in lymphocytes from patients and healthy controls was determined by immunofluorescence staining.,All results were correlated with the parasitaemia and the number of previous episodes of malaria.,The cytokine IL-10 plasma levels showed a significant increase in both patients with low (650.4 ± 59.3 pg/mL) and high (2870 ± 185.3 pg/mL) parasitaemia compared to the control (326.1 ± 40.1 pg/mL).,In addition, there was an increase of this cytokine in an episode dependent manner (individuals with no previous episodes of malaria - primoinfected: 363.9 ± 31.1 pg/mL; individuals with prior exposure: 659.9 ± 49.4 pg/mL).,The quantification of annexin-A1 expression indicated a decrease in CD4+ and CD8+ T cells and an increase in Treg in comparison with the control group.,When annexin-A1 expression was compared according to the number of previous episodes of malaria, patients who have been exposed more than once to the parasite was found to have higher levels of CD4+ T cells (96.0 ± 2.5 A.U) compared to primoinfected (50.3 ± 1.7).,However, this endogenous protein had higher levels in CD8+ (108.5 ± 3.1) and Treg (87.5 ± 2.5) from patients primoinfected.,This study demonstrates that in the patients infected with P. vivax the release of immunoregulatory molecules can be influenced by the parasitaemia level and the number of previous episodes of malaria. annexin-A1 is expressed differently in lymphocyte sub-populations and may have a role in cell proliferation.,Furthermore, annexin-A1 may be contributing to IL-10 release in plasma of patients with vivax malaria.

Plasmodium falciparum malaria causes 500 million clinical cases with approximately one million deaths each year.,After many years of exposure, individuals living in endemic areas develop a form of clinical immunity to disease known as premunition, which is characterised by low parasite burdens rather than sterilising immunity.,The reason why malaria parasites persist under a state of premunition is unknown but it has been suggested that suppression of protective immunity might be a mechanism leading to parasite persistence.,Although acquired immunity limits the clinical impact of infection and provides protection against parasite replication, experimental evidence indicates that cell-mediated immune responses also result in detrimental inflammation and contribute to the aetiology of severe disease.,Thus, an appropriate regulatory balance between protective immune responses and immune-mediated pathology is required for a favourable outcome of infection.,As natural regulatory T (Treg) cells are identified as an immunosuppressive lineage able to modulate the magnitude of effector responses, several studies have investigated whether this cell population plays a role in balancing protective immunity and pathogenesis during malaria.,The main findings to date are summarised in this review and the implication for the induction of pathogenesis and immunity to malaria is discussed.

Transfusion-transmitted (TT) malaria is an alternative infection route that has gained little attention from authorities, despite representing a life-threatening condition.,There has been no systematic review of this health problem in American countries.,The aim of this study was to describe the clinical and epidemiological characteristics of TT malaria in the Americas and identify factors associated with lethality based on the studies published in the literature.,Potentially relevant papers in all languages were retrieved from MEDLINE and LILACS.,Additional articles were obtained from reviews and original papers.,Publications on screening of candidate blood donors and on surveillance of TT malaria cases were included.,Odds ratios with respective 95% confidence intervals (95% CI) were calculated.,Epidemiological characteristics of blood donors of TT malaria cases, including a pooled positivity of different tests for malaria diagnosis, were retrieved.,A total of 63 publications regarding TT malaria from seven countries were included, from 1971 to 2016.,A total of 422 cases of TT malaria were recorded.,Most TT malaria cases were in females (62.0%) and 39.5% were in the ≥61 years-old age group.,About half of all cases were from Mexico (50.7%), 40.3% from the United States of America (USA) and 6.6% from Brazil.,Gyneco-obstetrical conditions (67.3%), surgical procedures (20.6%) and complications from neoplasias (6.1%) were the most common indications of transfusion.,Packed red blood cells (RBCs) (50.7%) and whole blood (43.3%) were the blood products mostly associated with TT malaria.,Cases were mostly caused by Plasmodium malariae (58.4%), followed by Plasmodium vivax (20.7%) and Plasmodium falciparum (17.9%).,A total of 66.6% of cases were diagnosed by microscopy.,Incubation period of 2-3 weeks was the most commonly observed (28.6%).,Lethality was seen in 5.3% of cases and was associated with living in non-endemic countries, P. falciparum infection and concomitant neoplastic diseases.,There is an important research and knowledge gap regarding the TT malaria burden in Latin American countries where malaria remains endemic.,No screening method that is practical, affordable and suitably sensitive is available at blood banks in Latin American countries, where infections with low parasitaemia contribute greatly to transmission.,Lethality from TT malaria was not negligible.,TT malaria needs to be acknowledged and addressed in areas moving toward elimination.,The online version of this article (doi:10.1186/s12936-017-1726-y) contains supplementary material, which is available to authorized users.

Brazil, a country of continental proportions, presents three profiles of malaria transmission.,The first and most important numerically, occurs inside the Amazon.,The Amazon accounts for approximately 60% of the nation’s territory and approximately 13% of the Brazilian population.,This region hosts 99.5% of the nation’s malaria cases, which are predominantly caused by Plasmodium vivax (i.e., 82% of cases in 2013).,The second involves imported malaria, which corresponds to malaria cases acquired outside the region where the individuals live or the diagnosis was made.,These cases are imported from endemic regions of Brazil (i.e., the Amazon) or from other countries in South and Central America, Africa and Asia.,Imported malaria comprised 89% of the cases found outside the area of active transmission in Brazil in 2013.,These cases highlight an important question with respect to both therapeutic and epidemiological issues because patients, especially those with falciparum malaria, arriving in a region where the health professionals may not have experience with the clinical manifestations of malaria and its diagnosis could suffer dramatic consequences associated with a potential delay in treatment.,Additionally, because the Anopheles vectors exist in most of the country, even a single case of malaria, if not diagnosed and treated immediately, may result in introduced cases, causing outbreaks and even introducing or reintroducing the disease to a non-endemic, receptive region.,Cases introduced outside the Amazon usually occur in areas in which malaria was formerly endemic and are transmitted by competent vectors belonging to the subgenus Nyssorhynchus (i.e., Anopheles darlingi, Anopheles aquasalis and species of the Albitarsis complex).,The third type of transmission accounts for only 0.05% of all cases and is caused by autochthonous malaria in the Atlantic Forest, located primarily along the southeastern Atlantic Coast.,They are caused by parasites that seem to be (or to be very close to) P. vivax and, in a less extent, by Plasmodium malariae and it is transmitted by the bromeliad mosquito Anopheles (Kerteszia) cruzii.,This paper deals mainly with the two profiles of malaria found outside the Amazon: the imported and ensuing introduced cases and the autochthonous cases.,We also provide an update regarding the situation in Brazil and the Brazilian endemic Amazon.

Four predictors were independently associated with an increased risk of death: acidosis, cerebral manifestations of malaria, elevated blood urea nitrogen, or signs of chronic illness.,The standard base deficit was found to be the single most relevant predictor of death.,Background.,Data from the largest randomized, controlled trial for the treatment of children hospitalized with severe malaria were used to identify such predictors of a poor outcome from severe malaria.,Methods.,African children (<15 years) with severe malaria participated in a randomized comparison of parenteral artesunate and parenteral quinine in 9 African countries.,Detailed clinical assessment was performed on admission.,Parasite densities were assessed in a reference laboratory.,Predictors of death were examined using a multivariate logistic regression model.,Results.,Twenty indicators of disease severity were assessed, out of which 5 (base deficit, impaired consciousness, convulsions, elevated blood urea, and underlying chronic illness) were associated independently with death.,Tachypnea, respiratory distress, deep breathing, shock, prostration, low pH, hyperparasitemia, severe anemia, and jaundice were statistically significant indicators of death in the univariate analysis but not in the multivariate model.,Age, glucose levels, axillary temperature, parasite density, heart rate, blood pressure, and blackwater fever were not related to death in univariate models.,Conclusions.,Acidosis, cerebral involvement, renal impairment, and chronic illness are key independent predictors for a poor outcome in African children with severe malaria.,Mortality is markedly increased in cerebral malaria combined with acidosis.,Clinical Trial Registration.,ISRCTN50258054.

Current Uganda National Malaria treatment guidelines recommend parasitological confirmation either by microscopy or rapid diagnostic test (RDT) before treatment with artemether-lumefantrine (AL).,However, the cost-effectiveness of these strategies has not been assessed at rural operational primary care centres.,Three health centres (HCs) were randomized to three diagnostic arms (microscopy, RDT and presumptive diagnosis) in a district of low and another of high malaria transmission intensities in Uganda.,Some 22,052 patients presenting with fever at outpatients departments were enrolled from March 2010 to February 2011.,Of these, a random sample of 1,627 was selected to measure additional socio-economic characteristics.,Costing was performed following the standard step-down cost allocation and the ingredients approach.,Effectiveness was measured as the number and proportion of patients correctly diagnosed and treated.,Incremental Cost-Effectiveness Ratios (ICERs) were estimated from the societal perspective (http://Clinicaltrials.gov, NCT00565071).,Overall RDT was most cost-effective with lowest ICER US$5.0 compared to microscopy US$9.61 per case correctly diagnosed and treated.,In the high transmission setting, ICER was US$4.38 for RDT and US$12.98 for microscopy.,The corresponding ICERs in the low transmission setting were US$5.85 and US$7.63 respectively.,The difference in ICERs between RDT and microscopy was greater in the high transmission area (US$8.9) than in low transmission setting (US$1.78).,At a willingness to pay of US$2.8, RDT remained cost effective up to a threshold value of the cost of treatment of US$4.7.,RDT was cost effective in both low and high transmission settings.,With a global campaign to reduce the costs of AL and RDT, the Malaria Control Programme and stakeholders need a strategy for malaria diagnosis because as the cost of AL decreases, presumptive treatment is likely to become more attractive.

A growing body of evidence suggests that dams intensify malaria transmission in sub-Saharan Africa.,However, the environmental characteristics underpinning patterns in malaria transmission around dams are poorly understood.,This study investigated local-scale environmental and meteorological variables linked to malaria transmission around three large dams in Ethiopia.,Monthly malaria incidence data (2010-2014) were collected from health centres around three dams located at lowland, midland and highland elevations in Ethiopia.,Environmental (elevation, distance from the reservoir shoreline, Normalized Difference Vegetation Index (NDVI), monthly reservoir water level, monthly changes in water level) and meteorological (precipitation, and minimum and maximum air temperature) data were analysed to determine their relationship with monthly malaria transmission at each dam using correlation and stepwise multiple regression analysis.,Village distance to reservoir shoreline (lagged by 1 and 2 months) and monthly change in water level (lagged by 1 month) were significantly correlated with malaria incidence at all three dams, while NDVI (lagged by 1 and 2 months) and monthly reservoir water level (lagged by 2 months) were found to have a significant influence at only the lowland and midland dams.,Precipitation (lagged by 1 and 2 months) was also significantly associated with malaria incidence, but only at the lowland dam, while minimum and maximum air temperatures (lagged by 1 and 2 months) were important factors at only the highland dam.,This study confirmed that reservoir-associated factors (distance from reservoir shoreline, monthly average reservoir water level, monthly water level change) were important predictors of increased malaria incidence in villages around Ethiopian dams in all elevation settings.,Reservoir water level management should be considered as an additional malaria vector control tool to help manage malaria transmission around dams.,The online version of this article (10.1186/s12936-019-2689-y) contains supplementary material, which is available to authorized users.

Reactive case detection is an approach that has been proposed as a tool for malaria elimination in low-transmission settings.,It is an intuitively justified approach based on the concept of space-time clustering of malaria cases.,When an index malaria clinical case is detected, it triggers reactive screening and treatment in the index house and neighbouring houses.,However, the efficacy of this approach at varying screening radii and malaria prevalence remains ill defined.,Data were obtained from a detailed demographic and geographic surveillance study in four villages on the Myanmar-Thailand border.,Clinical cases were recorded at village malaria clinics and were linked back to patients’ residencies.,These data were used to simulate the efficacy of reactive case detection for clinical cases using rapid diagnostic tests (RDT).,Simulations took clinical cases in a given month and tabulated the number of cases that would have been detected in the following month at varying screening radii around the index houses.,Simulations were run independently for both falciparum and vivax malaria.,Each simulation of a reactive case detection effort was run in comparison with a strategy using random selection of houses for screening.,In approximately half of the screenings for falciparum and 10% for vivax it would have been impossible to detect any malaria cases regardless of the screening strategy because the screening would have occurred during times when there were no cases.,When geographically linked cases were present in the simulation, reactive case detection would have only been successful at detecting most malaria cases using larger screening radii (150-m radius and above).,At this screening radius and above, reactive case detection does not perform better than random screening of an equal number of houses in the village.,Screening within very small radii detects only a very small proportion of cases, but despite this low performance is better than random screening with the same sample size.,The results of these simulations indicate that reactive case detection for clinical cases using RDTs has limited ability in halting transmission in regions of low and unstable transmission.,This is linked to high spatial heterogeneity of cases, acquisition of malaria infections outside the village, as well missing asymptomatic infections.,When cases are few and sporadic, reactive case detection would result in major time and budgetary losses.,The online version of this article (doi:10.1186/s12936-016-1631-9) contains supplementary material, which is available to authorized users.

Plasmodium falciparum infections with slow parasite clearance following artemisinin-based therapies are widespread in the Greater Mekong Subregion.,A molecular marker of the slow clearance phenotype has been identified: single genetic changes within the propeller region of the Kelch13 protein (pfk13; Pf3D7_1343700).,Global searches have identified almost 200 different non-synonymous mutant pfk13 genotypes.,Most mutations occur at low prevalence and have uncertain functional significance.,To characterize the impact of different pfk13 mutations on parasite clearance, we conducted an individual patient data meta-analysis of the associations between parasite clearance half-life (PC1/2) and pfk13 genotype based on a large set of individual patient records from Asia and Africa.,A systematic literature review following the PRISMA protocol was conducted to identify studies published between 2000 and 2017 which included frequent parasite counts and pfk13 genotyping.,Four databases (Ovid Medline, PubMed, Ovid Embase, and Web of Science Core Collection) were searched.,Eighteen studies (15 from Asia, 2 from Africa, and one multicenter study with sites on both continents) met inclusion criteria and were shared.,Associations between the log transformed PC1/2 values and pfk13 genotype were assessed using multivariable regression models with random effects for study site.,Both the pfk13 genotypes and the PC1/2 were available from 3250 (95%) patients (n = 3012 from Asia (93%), n = 238 from Africa (7%)).,Among Asian isolates, all pfk13 propeller region mutant alleles observed in five or more specific isolates were associated with a 1.5- to 2.7-fold longer geometric mean PC1/2 compared to the PC1/2 of wild type isolates (all p ≤ 0.002).,In addition, mutant allele E252Q located in the P. falciparum region of pfk13 was associated with 1.5-fold (95%CI 1.4-1.6) longer PC1/2.,None of the isolates from four countries in Africa showed a significant difference between the PC1/2 of parasites with or without pfk13 propeller region mutations.,Previously, the association of six pfk13 propeller mutant alleles with delayed parasite clearance had been confirmed.,This analysis demonstrates that 15 additional pfk13 alleles are associated strongly with the slow-clearing phenotype in Southeast Asia.,Pooled analysis associated 20 pfk13 propeller region mutant alleles with the slow clearance phenotype, including 15 mutations not confirmed previously.,The online version of this article (10.1186/s12916-018-1207-3) contains supplementary material, which is available to authorized users.

Malaria is a major public health problem in the Democratic Republic of Congo.,Despite progress achieved over the past decade in the fight against malaria, further efforts have to be done such as in the surveillance and the containment of Plasmodium falciparum resistant strains.,We investigated resistance to artemisinin-based combination therapies currently in use in Democratic Republic of Congo by surveying molecular polymorphisms in three genes: pfcrt, pfmdr1 and pfk13 to explore possible emergence of amodiaquine, lumefantrine or artemisinin resistance in Democratic Republic of Congo.,This study essentially revealed that resistance to chloroquine is still decreasing while polymorphism related to amodiaquine resistance seems to be not present in Democratic Republic of Congo, that three samples, located in the east of the country, harbor Pfmdr1 amplification and that none of the mutations found in South-East Asia correlated with artemisinine resistance have been found in Democratic Republic of Congo.,But new mutations have been identified, especially the M476K, occurred in the same position that the M476I previously identified in the F32-ART strain, strongly resistant to artemisinine.,Antimalarial first-line treatments currently in use in Democratic Republic of Congo are not associated with emergence of molecular markers of resistance.

Areas with dynamic population movements are likely to be associated with higher levels of drug-resistant malaria.,Myanmar Artemisinin Resistance Containment (MARC) Project has been launching since 2012.,One of its components includes enhancing strategic approaches for mobile/migrant populations.,We aimed to ascertain the estimated population of mobile migrant workers and their families in terms of stability in work setting in townships classified as tier II (areas with significant inflows of people from areas with credible evidence of artemisinin resistance) for Artemisinin resistance; to identify knowledge, attitudes and practices related to prevention and control of malaria and to recommend cost-effective strategies in planning for prevention and control of malaria.,A prospective cross-sectional study conducted between June to December 2013 that covered 1,899 migrant groups from 16 tier II townships of Bago Region, and Kayin and Kayah States.,Trained data collectors used a pre-tested and subsequently modified questionnaire and interviewed 2,381 respondents.,Data of migrant groups were analyzed and compared by category depending upon the stability of their work setting.,The estimated population of the 1,899 migrant groups categorized into three on the nature of their work setting was 56,030.,Bago region was the commonest reported source of origin of migrant groups as well as their transit.,Malaria volunteers were mostly within the reach of category 1 migrant groups (43/66, 65.2 %).,Less stable migrant groups in category 3 had limited access to malaria information (14.7 %) and malaria care providers (22.1 %), low level of awareness and use of long-lasting insecticide-treated nets (46.6 and 38.8 %).,Also, they had poor knowledge on malaria prevention on confirming suspected malaria and on using artemisinin combined therapy (ACT).,Within two weeks prior to the survey, only 16.5 % of respondents in all categories combined reported acute undifferentiated fever.,Mobility dynamics of migrant groups was complex and increased their vulnerability to malaria.,This phenomenon was accentuated in less stable areas.,Even though migrant workers were familiar with rapid diagnostic tests for malaria, ACT still needed wide recognition to improve practices supportive of MARC including the use of appropriate personal protection.,High mobility calls for re-designation of tier II townships to optimize ACT resistance containment.,The online version of this article (doi:10.1186/s12889-015-2241-0) contains supplementary material, which is available to authorized users.

With the encouraging advent of new malaria vaccine candidates, mathematical modelling of expected impacts of present and future vaccines as part of multi-intervention strategies is especially relevant.,The impact of potential malaria vaccines is presented utilizing the EMOD model, a comprehensive model of the vector life cycle coupled to a detailed mechanistic representation of intra-host parasite and immune dynamics.,Values of baseline transmission and vector feeding behaviour parameters are identified, for which local elimination is enabled by layering pre-erythrocytic vaccines of various efficacies on top of high and sustained insecticide-treated net coverage.,The expected reduction in clinical cases is further explored in a scenario that targets children by adding a pre-erythrocytic vaccine to the EPI programme for newborns.,At high transmission, there is a minimal reduction in clinical disease cases, as the time to infection is only slightly delayed.,At lower transmission, there is an accelerating community-level protection that has subtle dependences on heterogeneities in vector behaviour, ecology, and intervention coverage.,At very low transmission, the trend reverses as many children are vaccinated to prevent few cases.,The maximum-impact setting is one in which the impact of increasing bed net coverage has saturated, vector feeding is primarily outdoors, and transmission is just above the threshold where small perturbations from a vaccine intervention result in large community benefits.

The protozoan diseases Human African Trypanosomiasis (HAT), Chagas disease (CD), and leishmaniases span worldwide and therefore their impact is a universal concern.,The present regimen against kinetoplastid protozoan infections is poor and insufficient.,Target-based design expands the horizon of drug design and development and offers novel chemical entities and potential drug candidates to the therapeutic arsenal against the aforementioned neglected diseases.,In this review, we report the most promising targets of the main kinetoplastid parasites, as well as their corresponding inhibitors.,This overview is part of the Special Issue, entitled “Advances of Medicinal Chemistry against Kinetoplastid Protozoa (Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp.),Infections: Drug Design, Synthesis and Pharmacology”.

Chagas disease, the clinical presentation of T. cruzi infection, is a major human health concern.,While the acute phase of Chagas disease is typically asymptomatic and self-resolving, chronically infected individuals suffer numerous sequelae later in life.,Cardiomyopathies in particular are the most severe consequence of chronic Chagas disease and cannot be reversed solely by parasite load reduction.,To prioritize new therapeutic targets, we unbiasedly interrogated the host signaling events in heart tissues isolated from a Chagas disease mouse model using quantitative, multiplexed proteomics.,We defined the host response to infection at both the proteome and phospho-proteome levels.,The proteome showed an increase in the immune response and a strong repression of several mitochondrial proteins.,Complementing the proteome studies, the phospho-proteomic survey found an abundance of phospho-site alterations in plasma membrane and cytoskeletal proteins.,Bioinformatic analysis of kinase activity provided substantial evidence for the activation of NDRG2 and JNK/p38 kinases during Chagas disease.,A significant activation of DYRK2 and AMPKA2 and the inhibition of casein family kinases were also predicted.,We concluded our analyses by linking the diseased heart proteome profile to known therapeutic interventions, uncovering a potential to target mitochondrial proteins, secreted immune effectors and core kinases for the treatment of chronic Chagas disease.,Together, this study provides molecular insight into host proteome and phospho-proteome responses to T. cruzi infection in the heart for the first time, highlighting pathways that can be further validated for functional contributions to disease and suitability as drug targets.

In the fight against malaria new medicines are an essential weapon.,For the parts of the world where the current gold standard artemisinin combination therapies are active, significant improvements can still be made: for example combination medicines which allow for single dose regimens, cheaper, safer and more effective medicines, or improved stability under field conditions.,For those parts of the world where the existing combinations show less than optimal activity, the priority is to have activity against emerging resistant strains, and other criteria take a secondary role.,For new medicines to be optimal in malaria control they must also be able to reduce transmission and prevent relapse of dormant forms: additional constraints on a combination medicine.,In the absence of a highly effective vaccine, new medicines are also needed to protect patient populations.,In this paper, an outline definition of the ideal and minimally acceptable characteristics of the types of clinical candidate molecule which are needed (target candidate profiles) is suggested.,In addition, the optimal and minimally acceptable characteristics of combination medicines are outlined (target product profiles).,MMV presents now a suggested framework for combining the new candidates to produce the new medicines.,Sustained investment over the next decade in discovery and development of new molecules is essential to enable the long-term delivery of the medicines needed to combat malaria.

In south-eastern Senegal, malaria and onchocerciasis are co-endemic.,Onchocerciasis in this region has been controlled by once or twice yearly mass drug administration (MDA) with ivermectin (IVM) for over fifteen years.,Since laboratory-raised Anopheles gambiae s.s. are susceptible to ivermectin at concentrations found in human blood post-ingestion of IVM, it is plausible that a similar effect could be quantified in the field, and that IVM might have benefits as a malaria control tool.,In 2008 and 2009, wild-caught blood fed An. gambiae s.l. mosquitoes were collected from huts of three pairs of Senegalese villages before and after IVM MDAs.,Mosquitoes were held in an insectary to assess their survival rate, subsequently identified to species, and their blood meals were identified.,Differences in mosquito survival were statistically analysed using a Glimmix model.,Lastly, changes in the daily probability of mosquito survivorship surrounding IVM MDAs were calculated, and these data were inserted into a previously developed, mosquito age-structured model of malaria transmission.,Anopheles gambiae s.s.,(P < 0.0001) and Anopheles arabiensis (P = 0.0191) from the treated villages had significantly reduced survival compared to those from control villages.,Furthermore, An gambiae s.s. caught 1-6 days after MDA in treated villages had significantly reduced survival compared to control village collections (P = 0.0003), as well as those caught pre-MDA (P < 0.0001) and >7 days post-MDA (P < 0.0001).,The daily probability of mosquito survival dropped >10% for the six days following MDA.,The mosquito age-structured model of malaria transmission demonstrated that a single IVM MDA would reduce malaria transmission (Ro) below baseline for at least eleven days, and that repeated IVM MDAs would result in a sustained reduction in malaria Ro.,Ivermectin MDA significantly reduced the survivorship of An. gambiae s.s. for six days past the date of the MDA, which is sufficient to temporarily reduce malaria transmission.,Repeated IVM MDAs could be a novel and integrative malaria control tool in areas with seasonal transmission, and which would have simultaneous impacts on neglected tropical diseases in the same villages.

Schistosoma mansoni is a parasitic flatworm causing schistosomiasis, an infectious disease affecting several hundred million people worldwide.,Schistosomes live dioeciously, and upon pairing with the male, the female starts massive egg production, which causes pathology.,Praziquantel (PZQ) is the only drug used, but it has an inherent risk of resistance development.,Therefore, alternatives are needed.,In the context of drug repurposing, the cancer drug imatinib was tested, showing high efficacy against S. mansoni in vitro.,Besides the gonads, imatinib mainly affected the integrity of the intestine in males and females.,In this study, we investigated the potential uptake and distribution of imatinib in adult schistosomes including its distribution kinetics.,To this end, we applied for the first time atmospheric-pressure scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging (AP-SMALDI MSI) for drug imaging in paired S. mansoni.,Our results indicate that imatinib was present in the esophagus and intestine of the male as early as 20 min after in vitro exposure, suggesting an oral uptake route.,After one hour, the drug was also found inside the paired female.,The detection of the main metabolite, N-desmethyl imatinib, indicated metabolization of the drug.,Additionally, a marker signal for the female ovary was successfully applied to facilitate further conclusions regarding organ tropism of imatinib.,Our results demonstrate that AP-SMALDI MSI is a useful method to study the uptake, tissue distribution, and metabolization of imatinib in S. mansoni.,The results suggest using AP-SMALDI MSI also for investigating other antiparasitic compounds and their metabolites in schistosomes and other parasites.,The online version contains supplementary material available at 10.1007/s00216-021-03230-w.

Schistosomiasis (bilharzia) is a neglected tropical disease caused by parasitic flatworms of the genus Schistosoma, with considerable morbidity in parts of the Middle East, South America, Southeast Asia, in sub-Saharan Africa, and particularly also in Europe.,The WHO describes an increasing global health burden with more than 290 million people threatened by the disease and a potential to spread into regions with temperate climates like Corsica, France.,The aim of our study was to investigate the influence of S. mansoni infection on colorectal carcinogenic signaling pathways in vivo and in vitro.,S. mansoni infection, soluble egg antigens (SEA) and the Interleukin-4-inducing principle from S. mansoni eggs induce Wnt/β-catenin signaling and the protooncogene c-Jun as well as downstream factor Cyclin D1 and markers for DNA-damage, such as Parp1 and γH2a.x in enterocytes.,The presence of these characteristic hallmarks of colorectal carcinogenesis was confirmed in colon biopsies from S. mansoni-infected patients demonstrating the clinical relevance of our findings.,For the first time it was shown that S. mansoni SEA may be involved in the induction of colorectal carcinoma-associated signaling pathways.

Artesunate-amodiaquine is a potential therapy for uncomplicated malaria in Cambodia.,Between September 2016 and January 2017, artesunate-amodiaquine efficacy and safety were evaluated in a prospective, open-label, single-arm observational study at health centers in Mondulkiri, Pursat, and Siem Reap Provinces, Cambodia.,Adults and children with microscopically confirmed Plasmodium falciparum malaria received oral artesunate-amodiaquine once daily for 3 days plus single-dose primaquine, with follow-up on days 7, 14, 21, and 28.,The primary outcome was day-28 polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR).,An amodiaquine parasite survival assay (AQSA) was developed and applied to whole genome sequencing results to evaluate potential amodiaquine resistance molecular markers.,In 63 patients, day-28 PCR-adjusted ACPR was 81.0% (95% confidence interval [CI], 68.9-88.7).,Day 3 parasite positivity rate was 44.4% (28/63; 95% CI, 31.9-57.5).,All 63 isolates had the K13(C580Y) marker for artemisinin resistance; 79.4% (50/63) had Pfpm2 amplification.,The AQSA resistance phenotype (≥45% parasite survival) was expressed in 36.5% (23/63) of isolates and was significantly associated with treatment failure (P = .0020).,Pfmdr1 mutant haplotypes were N86/184F/D1246, and Pfcrt was CVIET or CVIDT at positions 72-76.,Additional Pfcrt mutations were not associated with amodiaquine resistance, but the G353V mutant allele was associated with ACPR compared to Pfmdr1 haplotypes harboring F1068L or S784L/R945P mutations (P = .030 and P = .0004, respectively).,For uncomplicated falciparum malaria in Cambodia, artesunate-amodiaquine had inadequate efficacy owing to amodiaquine-resistant P. falciparum.,Amodiaquine resistance was not associated with previously identified molecular markers.,Artesunate-amodiaquine has inadequate efficacy in Cambodian patients with uncomplicated falciparum malaria.,Amodiaquine resistance is present in Cambodia and not associated with molecular markers reported in Africa and South America.

Artemisinin and partner-drug resistance in Plasmodium falciparum are major threats to malaria control and elimination.,Triple artemisinin-based combination therapies (TACTs), which combine existing co-formulated ACTs with a second partner drug that is slowly eliminated, might provide effective treatment and delay emergence of antimalarial drug resistance.,In this multicentre, open-label, randomised trial, we recruited patients with uncomplicated P falciparum malaria at 18 hospitals and health clinics in eight countries.,Eligible patients were aged 2-65 years, with acute, uncomplicated P falciparum malaria alone or mixed with non-falciparum species, and a temperature of 37·5°C or higher, or a history of fever in the past 24 h.,Patients were randomly assigned (1:1) to one of two treatments using block randomisation, depending on their location: in Thailand, Cambodia, Vietnam, and Myanmar patients were assigned to either dihydroartemisinin-piperaquine or dihydroartemisinin-piperaquine plus mefloquine; at three sites in Cambodia they were assigned to either artesunate-mefloquine or dihydroartemisinin-piperaquine plus mefloquine; and in Laos, Myanmar, Bangladesh, India, and the Democratic Republic of the Congo they were assigned to either artemether-lumefantrine or artemether-lumefantrine plus amodiaquine.,All drugs were administered orally and doses varied by drug combination and site.,Patients were followed-up weekly for 42 days.,The primary endpoint was efficacy, defined by 42-day PCR-corrected adequate clinical and parasitological response.,Primary analysis was by intention to treat.,A detailed assessment of safety and tolerability of the study drugs was done in all patients randomly assigned to treatment.,This study is registered at ClinicalTrials.gov, NCT02453308, and is complete.,Between Aug 7, 2015, and Feb 8, 2018, 1100 patients were given either dihydroartemisinin-piperaquine (183 [17%]), dihydroartemisinin-piperaquine plus mefloquine (269 [24%]), artesunate-mefloquine (73 [7%]), artemether-lumefantrine (289 [26%]), or artemether-lumefantrine plus amodiaquine (286 [26%]).,The median age was 23 years (IQR 13 to 34) and 854 (78%) of 1100 patients were male.,In Cambodia, Thailand, and Vietnam the 42-day PCR-corrected efficacy after dihydroartemisinin-piperaquine plus mefloquine was 98% (149 of 152; 95% CI 94 to 100) and after dihydroartemisinin-piperaquine was 48% (67 of 141; 95% CI 39 to 56; risk difference 51%, 95% CI 42 to 59; p<0·0001).,Efficacy of dihydroartemisinin-piperaquine plus mefloquine in the three sites in Myanmar was 91% (42 of 46; 95% CI 79 to 98) versus 100% (42 of 42; 95% CI 92 to 100) after dihydroartemisinin-piperaquine (risk difference 9%, 95% CI 1 to 17; p=0·12).,The 42-day PCR corrected efficacy of dihydroartemisinin-piperaquine plus mefloquine (96% [68 of 71; 95% CI 88 to 99]) was non-inferior to that of artesunate-mefloquine (95% [69 of 73; 95% CI 87 to 99]) in three sites in Cambodia (risk difference 1%; 95% CI −6 to 8; p=1·00).,The overall 42-day PCR-corrected efficacy of artemether-lumefantrine plus amodiaquine (98% [281 of 286; 95% CI 97 to 99]) was similar to that of artemether-lumefantrine (97% [279 of 289; 95% CI 94 to 98]; risk difference 2%, 95% CI −1 to 4; p=0·30).,Both TACTs were well tolerated, although early vomiting (within 1 h) was more frequent after dihydroartemisinin-piperaquine plus mefloquine (30 [3·8%] of 794) than after dihydroartemisinin-piperaquine (eight [1·5%] of 543; p=0·012).,Vomiting after artemether-lumefantrine plus amodiaquine (22 [1·3%] of 1703) and artemether-lumefantrine (11 [0·6%] of 1721) was infrequent.,Adding amodiaquine to artemether-lumefantrine extended the electrocardiogram corrected QT interval (mean increase at 52 h compared with baseline of 8·8 ms [SD 18·6] vs 0·9 ms [16·1]; p<0·01) but adding mefloquine to dihydroartemisinin-piperaquine did not (mean increase of 22·1 ms [SD 19·2] for dihydroartemisinin-piperaquine vs 20·8 ms [SD 17·8] for dihydroartemisinin-piperaquine plus mefloquine; p=0·50).,Dihydroartemisinin-piperaquine plus mefloquine and artemether-lumefantrine plus amodiaquine TACTs are efficacious, well tolerated, and safe treatments of uncomplicated P falciparum malaria, including in areas with artemisinin and ACT partner-drug resistance.,UK Department for International Development, Wellcome Trust, Bill & Melinda Gates Foundation, UK Medical Research Council, and US National Institutes of Health.

The southwestern region of China, along the Myanmar border, has accounted for the highest number of cases of imported malaria since China shifted from a malaria control program to an elimination strategy in 2010.,We conducted a retrospective study, in which 623 medical charts were analyzed to provide an epidemiological characterization of malaria cases that were diagnosed and treated at the People's Hospital of Tengchong County (PHTC), located in southwestern China, from 2008 to 2013.,Our aim was to understand the characteristics of malaria in this region, which is a high-endemic region with imported cases.,The majority of patients were male (91.7%), and the average age was 32.4 years.,Most of the patients (86.4%) had visited Myanmar; labor was the purpose of travel for 63.9% of the patients.,Plasmodium vivax and Plasmodium falciparum were responsible for 53.8% and 34.9% of the infections, respectively.,The number of hospitalized patients rose gradually from 2008 to 2010 and reached its peak in 2010 (191).,After 2010, the number of hospitalized cases fell rapidly from 191 (2010) to 45 (2013), and the proportion of patients who lived in the forest and the number infected with P. falciparum also fell.,In conclusion, the number of hospitalized patients in the southwestern region of China, Tengchong county, decreased after China implemented a malaria elimination strategy in 2010.,However, migrant workers returning from Myanmar remained important contributors to cases of imported malaria.,The management of imported malaria should be targeted by the malaria elimination program in China.

Malaria importation and local vector susceptibility to imported Plasmodium vivax infection are a continuing risk along the China-Myanmar border.,Malaria transmission has been prevented in 3 border villages in Tengchong County, Yunnan Province, China, by use of active fever surveillance, integrated vector control measures, and intensified surveillance and response.

Chloroquine is the first-line treatment for Plasmodium vivax malaria in most endemic countries, but resistance is increasing.,Monitoring of antimalarial efficacy is essential, but in P vivax infections the assessment of treatment efficacy is confounded by relapse from the dormant liver stages.,We systematically reviewed P vivax malaria treatment efficacy studies to establish the global extent of chloroquine resistance.,We searched Medline, Web of Science, Embase, and the Cochrane Database of Systematic Reviews to identify studies published in English between Jan 1, 1960, and April 30, 2014, which investigated antimalarial treatment efficacy in P vivax malaria.,We excluded studies that did not include supervised schizonticidal treatment without primaquine.,We determined rates of chloroquine resistance according to P vivax malaria recurrence rates by day 28 whole-blood chloroquine concentrations at the time of recurrence and study enrolment criteria.,We identified 129 eligible clinical trials involving 21 694 patients at 179 study sites and 26 case reports describing 54 patients.,Chloroquine resistance was present in 58 (53%) of 113 assessable study sites, spread across most countries that are endemic for P vivax.,Clearance of parasitaemia assessed by microscopy in 95% of patients by day 2, or all patients by day 3, was 100% predictive of chloroquine sensitivity.,Heterogeneity of study design and analysis has confounded global surveillance of chloroquine-resistant P vivax, which is now present across most countries endemic for P vivax.,Improved methods for monitoring of drug resistance are needed to inform antimalarial policy in these regions.,Wellcome Trust (UK).

Many recent studies have examined the impact of urbanization on Plasmodium falciparum malaria endemicity and found a general trend of reduced transmission in urban areas.,However, none has examined the effect of urbanization on Plasmodium vivax malaria, which is the most widely distributed malaria species and can also cause severe clinical syndromes in humans.,In this study, a set of 10,003 community-based P. vivax parasite rate (PvPR) surveys are used to explore the relationships between PvPR in urban and rural settings.,The PvPR surveys were overlaid onto a map of global urban extents to derive an urban/rural assignment.,The differences in PvPR values between urban and rural areas were then examined.,Groups of PvPR surveys inside individual city extents (urban) and surrounding areas (rural) were identified to examine the local variations in PvPR values.,Finally, the relationships of PvPR between urban and rural areas within the ranges of 41 dominant Anopheles vectors were examined.,Significantly higher PvPR values in rural areas were found globally.,The relationship was consistent at continental scales when focusing on Africa and Asia only, but in the Americas, significantly lower values of PvPR in rural areas were found, though the numbers of surveys were small.,Moreover, except for the countries in the Americas, the same trends were found at national scales in African and Asian countries, with significantly lower values of PvPR in urban areas.,However, the patterns at city scales among 20 specific cities where sufficient data were available were less clear, with seven cities having significantly lower PvPR values in urban areas and two cities showing significantly lower PvPR in rural areas.,The urban-rural PvPR differences within the ranges of the dominant Anopheles vectors were generally, in agreement with the regional patterns found.,Except for the Americas, the patterns of significantly lower P. vivax transmission in urban areas have been found globally, regionally, nationally and by dominant vector species here, following trends observed previously for P. falciparum.,To further understand these patterns, more epidemiological, entomological and parasitological analyses of the disease at smaller spatial scales are needed.

Plasmodium vivax exacts a significant toll on health worldwide, yet few efforts to date have quantified the extent and temporal trends of its global distribution.,Given the challenges associated with the proper diagnosis and treatment of P vivax, national malaria programmes-particularly those pursuing malaria elimination strategies-require up to date assessments of P vivax endemicity and disease impact.,This study presents the first global maps of P vivax clinical burden from 2000 to 2017.,In this spatial and temporal modelling study, we adjusted routine malariometric surveillance data for known biases and used socioeconomic indicators to generate time series of the clinical burden of P vivax.,These data informed Bayesian geospatial models, which produced fine-scale predictions of P vivax clinical incidence and infection prevalence over time.,Within sub-Saharan Africa, where routine surveillance for P vivax is not standard practice, we combined predicted surfaces of Plasmodium falciparum with country-specific ratios of P vivax to P falciparum.,These results were combined with surveillance-based outputs outside of Africa to generate global maps.,We present the first high-resolution maps of P vivax burden.,These results are combined with those for P falciparum (published separately) to form the malaria estimates for the Global Burden of Disease 2017 study.,The burden of P vivax malaria decreased by 41·6%, from 24·5 million cases (95% uncertainty interval 22·5-27·0) in 2000 to 14·3 million cases (13·7-15·0) in 2017.,The Americas had a reduction of 56·8% (47·6-67·0) in total cases since 2000, while South-East Asia recorded declines of 50·5% (50·3-50·6) and the Western Pacific regions recorded declines of 51·3% (48·0-55·4).,Europe achieved zero P vivax cases during the study period.,Nonetheless, rates of decline have stalled in the past five years for many countries, with particular increases noted in regions affected by political and economic instability.,Our study highlights important spatial and temporal patterns in the clinical burden and prevalence of P vivax.,Amid substantial progress worldwide, plateauing gains and areas of increased burden signal the potential for challenges that are greater than expected on the road to malaria elimination.,These results support global monitoring systems and can inform the optimisation of diagnosis and treatment where P vivax has most impact.,Bill & Melinda Gates Foundation and the Wellcome Trust.

The human malaria parasite Plasmodium vivax infects red blood cells through a key pathway that requires interaction between Duffy binding protein II (DBPII) and its receptor on reticulocytes, the Duffy antigen/receptor for chemokines (DARC).,A high proportion of P. vivax-exposed individuals fail to develop antibodies that inhibit DBPII-DARC interaction, and genetic factors that modulate this humoral immune response are poorly characterized.,Here, we investigate if DBPII responsiveness could be HLA class II-linked.,A community-based open cohort study was carried out in an agricultural settlement of the Brazilian Amazon, in which 336 unrelated volunteers were genotyped for HLA class II (DRB1, DQA1 and DQB1 loci), and their DBPII immune responses were monitored over time (baseline, 6 and 12 months) by conventional serology (DBPII IgG ELISA-detected) and functional assays (inhibition of DBPII-erythrocyte binding).,The results demonstrated an increased susceptibility of the DRB1*13:01 carriers to develop and sustain an anti-DBPII IgG response, while individuals with the haplotype DRB1*14:02-DQA1*05:03-DQB1*03:01 were persistent non-responders.,HLA class II gene polymorphisms also influenced the functional properties of DBPII antibodies (BIAbs, binding inhibitory antibodies), with three alleles (DRB1*07:01, DQA1*02:01 and DQB1*02:02) comprising a single haplotype linked with the presence and persistence of the BIAbs response.,Modelling the structural effects of the HLA-DRB1 variants revealed a number of differences in the peptide-binding groove, which is likely to lead to altered antigen binding and presentation profiles, and hence may explain the differences in subject responses.,The current study confirms the heritability of the DBPII antibody response, with genetic variation in HLA class II genes influencing both the development and persistence of IgG antibody responses.,Cellular studies to increase knowledge of the binding affinities of DBPII peptides for class II molecules linked with good or poor antibody responses might lead to the development of strategies for controlling the type of helper T cells activated in response to DBPII.

Malaria elimination requires diagnostic methods able to detect parasite levels well below what is currently possible with microscopy and rapid diagnostic tests.,This is particularly true in surveillance of malaria at the population level that includes so-called “asymptomatic” individuals.,The development of the first ultrasensitive loop mediated amplification method capable of detecting malaria from both whole blood and dried blood spots (DBS) is described.,The 18S rRNA and corresponding genes that remain stable on DBS for up to 5 months are targeted.,In the case of Plasmodium falciparum, lower limits of detection of 25 parasite/mL and 50-100 parasite/mL from whole blood and DBS were obtained, respectively.,A sensitivity of 97.0% (95% CI 82.5-99.8) and specificity of 99.1% (95% CI 97.6-99.7) was obtained for the detection of all species in asymptomatic individuals from Africa and Asia (n = 494).,This tool is ideally suited for low middle-income countries where malaria is endemic and ultrasensitive surveillance of malaria is highly desirable for elimination.

Rapid diagnostic tests (RDTs) have transformed malaria diagnosis.,The most prevalent P. falciparum RDTs detect histidine-rich protein 2 (PfHRP2).,However, pfhrp2 gene deletions yielding false-negative RDTs, first reported in South America in 2010, have been confirmed in Africa and Asia.,We developed a mathematical model to explore the potential for RDT-led diagnosis to drive selection of pfhrp2-deleted parasites.,Low malaria prevalence and high frequencies of people seeking treatment resulted in the greatest selection pressure.,Calibrating our model against confirmed pfhrp2-deletions in the Democratic Republic of Congo, we estimate a starting frequency of 6% pfhrp2-deletion prior to RDT introduction.,Furthermore, the patterns observed necessitate a degree of selection driven by the introduction of PfHRP2-based RDT-guided treatment.,Combining this with parasite prevalence and treatment coverage estimates, we map the model-predicted spread of pfhrp2-deletion, and identify the geographic regions in which surveillance for pfhrp2-deletion should be prioritised.,Since the turn of the millennium, a large increase in international funding has helped to reduce the public health impact of malaria.,The introduction of rapid diagnostic tests has played a central role in these efforts, particularly in remote areas that are heavily affected by the disease.,These tests analyse human blood samples for specific proteins that are produced by malaria parasites.,The most common rapid diagnostic tests for malaria detect a protein called HRP2, which is produced by the deadliest malaria parasite, Plasmodium falciparum.,Recently, however, cases have emerged where the tests have failed to detect these malaria infections.,The first occurred in South America, and were found to be because some malaria parasites no longer possessed the gene that produces HRP2.,Since then, malaria parasites that lack this gene have been found in several locations in Africa.,This raises the question of whether using the tests favours the survival and spread of parasites that cannot produce the HRP2 protein.,Using mathematical modelling techniques, Watson et al. now present evidence that suggests that the use of HRP2-detecting rapid diagnostic tests over the past 10 years could have favoured the evolution of malaria parasites that lack this protein.,Furthermore, the models suggest that the conditions that are most likely to cause such selection are places where malaria infections are not common but people seek treatment at high rates.,Using this information, Watson et al. created a map of 160 locations in Africa most at risk of rapid diagnostic test-driven selection against the gene that produces HRP2.,Public health authorities could use these maps to determine where they should more closely monitor malaria parasites to see if they lack this gene.,Future genetic investigations will be required in the high-risk areas to confirm and refine the predictions.,The development of rapid diagnostic tests that detect other malaria proteins will also be essential if malaria parasites that lack HRP2 continue to spread.

A longitudinal cohort study of multispecies Plasmodium infections in mothers and children in Uganda has revealed there to be both persistent and increasing parasitemia of certain species, which has clinical significance, despite regular access to frontline antimalarial treatments.,As part of a longitudinal cohort investigation of intestinal schistosomiasis and malaria in Ugandan children and their mothers on the shorelines of Lakes Victoria and Albert, we documented risk factors and morbidity associated with nonfalciparum Plasmodium infections and the longitudinal dynamics of Plasmodium species in children.,Host age, household location, and Plasmodium falciparum infection were strongly associated with nonfalciparum Plasmodium infections, and Plasmodium malariae infection was associated with splenomegaly.,Despite regular artemisinin combination therapy treatment, there was a 3-fold rise in P. malariae prevalence, which was not accountable for by increasing age of the child.,Worryingly, our findings reveal the consistent emergence of nonfalciparum infections in children, highlighting the complex dynamics underlying multispecies infections here.,Given the growing body of evidence that nonfalciparum malaria infections cause significant morbidity, we encourage better surveillance for nonfalciparum Plasmodium infections, particularly in children, with more sensitive DNA detection methods and improved field-based diagnostics.

Asymptomatic malaria infections represent a major challenge in malaria control and elimination in Africa.,They are reservoirs of malaria parasite that can contribute to disease transmission.,Therefore, identification and control of asymptomatic infections are important to make malaria elimination feasible.,In this study, we investigated the extent and distribution of asymptomatic malaria in Western Kenya and examined how varying parasitemia affects performance of diagnostic methods including microscopy, conventional PCR, and quantitative PCR.,In addition, we compared parasite prevalence rates and parasitemia levels with respect to topography and age in order to explore factors that influence malaria infection.,Over 11,000 asymptomatic blood samples from children and adolescents up to 18 years old representing broad areas of Western Kenya were included.,Quantitative PCR revealed the highest parasite positive rate among all methods and malaria prevalence in western Kenya varied widely from less than 1% to over 50%.,A significantly lower parasitemia was detected in highland than in lowland samples and this contrast was also observed primarily among submicroscopic samples.,Although we found no correlation between parasitemia level and age, individuals of younger age group (aged <14) showed significantly higher parasite prevalence.,In the lowlands, individuals of aged 5-14 showed significantly higher prevalence than those under age 5.,Our findings highlight the need for a more sensitive and time-efficient assay for asymptomatic malaria detection particularly in areas of low-transmission.,Combining QPCR with microscopy can enhance the capacity of detecting submicroscopic asymptomatic malaria infections.

To compare the performance of the Paracheck™ rapid diagnostic test (RDT) with microscopy for diagnosing malaria in hospitalised children.,Children aged between 2 months and 13 years with fever were enrolled in the study over 1 year.,A standard clinical history and examination were recorded and blood drawn for culture, complete blood count, Paracheck™ RDT and double-read blood slide.,Of 3639 children enrolled, 2195 (60.3%) were slide positive.,The sensitivity and specificity of Paracheck were 97.5% (95% CI 96.9-98.0) and 65.3% (95% CI 63.8-66.9), respectively.,There was an inverse relationship between age-specific prevalence of parasitaemia and Paracheck specificity.,In logistic regression model, false-positive Paracheck results were significantly associated with pre-admission use of antimalarial drug (OR 1.44, 95% CI 1.16-1.78), absence of current fever (OR 0.64, 95% CI 0.52-0.79) and non-typhi Salmonella bacteraemia (OR 3.89.,95% CI 2.27-6.63).,In spite of high sensitivity, 56/2195 (2.6%) of true infections were Paracheck negative and 8/56 (14.3%) were in patients with >50 000 parasites/μl.,Paracheck had poor specificity in diagnosing malaria in severely ill children; this was likely to be due to HRP2 persistence following recent parasite clearance.,The combination of positive Paracheck and negative blood slide results identified a group of children at high risk of non-typhi Salmonella infection.,While Paracheck was highly sensitive, some high-density infections were missed.,For children with severe febrile illness, at least two reliable negative parasitological test results should be available to justify withholding antimalarial treatment; the optimal choice of these has yet to be identified.

Malaria rapid diagnostics tests (RDTs) can increase availability of laboratory-based diagnosis and improve the overall management of febrile patients in malaria endemic areas.,In preparation to scale-up RDTs in health facilities in Malawi, an evaluation of four RDTs to help guide national-level decision-making was conducted.,A cross sectional study of four histidine rich-protein-type-2- (HRP2) based RDTs at four health centres in Blantyre, Malawi, was undertaken to evaluate the sensitivity and specificity of RDTs, assess prescriber adherence to RDT test results and explore operational issues regarding RDT implementation.,Three RDTs were evaluated in only one health centre each and one RDT was evaluated in two health centres.,Light microscopy in a reference laboratory was used as the gold standard.,A total of 2,576 patients were included in the analysis.,All of the RDTs tested had relatively high sensitivity for detecting any parasitaemia [Bioline SD (97%), First response malaria (92%), Paracheck (91%), ICT diagnostics (90%)], but low specificity [Bioline SD (39%), First response malaria (42%), Paracheck (68%), ICT diagnostics (54%)].,Specificity was significantly lower in patients who self-treated with an anti-malarial in the previous two weeks (odds ratio (OR) 0.5; p-value < 0.001), patients 5-15 years old versus patients > 15 years old (OR 0.4, p-value < 0.001) and when the RDT was performed by a community health worker versus a laboratory technician (OR 0.4; p-value < 0.001).,Health workers correctly prescribed anti-malarials for patients with positive RDT results, but ignored negative RDT results with 58% of patients with a negative RDT result treated with an anti-malarial.,The results of this evaluation, combined with other published data and global recommendations, have been used to select RDTs for national scale-up.,In addition, the study identified some key issues that need to be further delineated: the low field specificity of RDTs, variable RDT performance by different cadres of health workers and the need for a robust quality assurance system.,Close monitoring of RDT scale-up will be needed to ensure that RDTs truly improve malaria case management.

Gastrointestinal disease caused by the apicomplexan parasite Cryptosporidium parvum is one of the most important diseases of young ruminant livestock, particularly neonatal calves.,Infected animals may suffer from profuse watery diarrhoea, dehydration and in severe cases death can occur.,At present, effective therapeutic and preventative measures are not available and a better understanding of the host-pathogen interactions is required.,Cryptosporidium parvum is also an important zoonotic pathogen causing severe disease in people, with young children being particularly vulnerable.,Our knowledge of the immune responses induced by Cryptosporidium parasites in clinically relevant hosts is very limited.,This review discusses the impact of bovine cryptosporidiosis and describes how a thorough understanding of the host-pathogen interactions may help to identify novel prevention and control strategies.

In this study, we examined the prevalence and molecular characteristics of Cryptosporidium in buffalo, dairy cattle and sheep in different farms at Kafr El Sheikh Province, Egypt.,Rectal fecal samples, including 466 samples from buffalo, 1697 from cattle and 120 from sheep, were collected from different ages and screened by modified Ziehl-Neelsen acid-fast microscopy for detection of Cryptosporidium oocysts.,All studied farms were positives with an overall prevalence of 1.29% in buffalo (4.17% in claves versus 0.48% in adults), 7.07% in cattle (6.90% in calves versus 10.20% and 6.10% in heifers and adults, respectively) and 2.50% in sheep (4.40% in lambs versus 1.30% in adults).,PCR-RFLP analyses of small-subunit rRNA genes from positive specimens revealed the occurrence of C. parvum and C. ryanae in buffalo; C. parvum, C. ryanae, C. bovis and C. andersoni in cattle and only C. xiaoi in sheep.,Genotypes distribution showed that C. ryanae was the dominant species (60.0%) followed by C. parvum (40.0%) in buffalo calves.,Meanwhile, in cattle calves, C. parvum was the commonest species (74.23%) followed by C. ryanae (16.10%) and C. bovis (9.70%).,Subtyping of C. parvum based on sequence analysis of the polymorphic 60 kDa glycoprotein gene locus showed the presence of subtypes IIdA20G1 and IIaA15G1R1 in both buffalo and cattle calves, addressing the potential role of calves in zoonotic cryptosporidiosis in Egypt.

As part of a World Health Organization-led effort to update the empirical evidence base for the leishmaniases, national experts provided leishmaniasis case data for the last 5 years and information regarding treatment and control in their respective countries and a comprehensive literature review was conducted covering publications on leishmaniasis in 98 countries and three territories (see ‘Leishmaniasis Country Profiles Text S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, S25, S26, S27, S28, S29, S30, S31, S32, S33, S34, S35, S36, S37, S38, S39, S40, S41, S42, S43, S44, S45, S46, S47, S48, S49, S50, S51, S52, S53, S54, S55, S56, S57, S58, S59, S60, S61, S62, S63, S64, S65, S66, S67, S68, S69, S70, S71, S72, S73, S74, S75, S76, S77, S78, S79, S80, S81, S82, S83, S84, S85, S86, S87, S88, S89, S90, S91, S92, S93, S94, S95, S96, S97, S98, S99, S100, S101’).,Additional information was collated during meetings conducted at WHO regional level between 2007 and 2011.,Two questionnaires regarding epidemiology and drug access were completed by experts and national program managers.,Visceral and cutaneous leishmaniasis incidence ranges were estimated by country and epidemiological region based on reported incidence, underreporting rates if available, and the judgment of national and international experts.,Based on these estimates, approximately 0.2 to 0.4 cases and 0.7 to 1.2 million VL and CL cases, respectively, occur each year.,More than 90% of global VL cases occur in six countries: India, Bangladesh, Sudan, South Sudan, Ethiopia and Brazil.,Cutaneous leishmaniasis is more widely distributed, with about one-third of cases occurring in each of three epidemiological regions, the Americas, the Mediterranean basin, and western Asia from the Middle East to Central Asia.,The ten countries with the highest estimated case counts, Afghanistan, Algeria, Colombia, Brazil, Iran, Syria, Ethiopia, North Sudan, Costa Rica and Peru, together account for 70 to 75% of global estimated CL incidence.,Mortality data were extremely sparse and generally represent hospital-based deaths only.,Using an overall case-fatality rate of 10%, we reach a tentative estimate of 20,000 to 40,000 leishmaniasis deaths per year.,Although the information is very poor in a number of countries, this is the first in-depth exercise to better estimate the real impact of leishmaniasis.,These data should help to define control strategies and reinforce leishmaniasis advocacy.

'One Health' proposes the unification of medical and veterinary sciences with the establishment of collaborative ventures in clinical care, surveillance and control of cross-species disease, education, and research into disease pathogenesis, diagnosis, therapy and vaccination.,The concept encompasses the human population, domestic animals and wildlife, and the impact that environmental changes ('environmental health') such as global warming will have on these populations.,Visceral leishmaniasis is a perfect example of a small companion animal disease for which prevention and control might abolish or decrease the suffering of canine and human patients, and which aligns well with the One Health approach.,In this review we discuss how surveillance for leishmaniases is undertaken globally through the control of anthroponootic visceral leishmaniasis (AVL) and zoonotic visceral leishmaniasis (ZVL).,The ZVL epidemic has been managed to date by the culling of infected dogs, treatment of human cases and control of the sandfly vector by insecticidal treatment of human homes and the canine reservoir.,Recently, preventive vaccination of dogs in Brazil has led to reduction in the incidence of the canine and human disease.,Vaccination permits greater dog owner compliance with control measures than a culling programme.,Another advance in disease control in Africa is provided by a surveillance programme that combines remote satellite sensing, ecological modelling, vector surveillance and geo-spatial mapping of the distribution of vectors and of the animal-to-animal or animal-to-human pathogen transmission.,This coordinated programme generates advisory notices and alerts on emerging infectious disease outbreaks that may impede or avoid the spreading of visceral leishmaniasis to new areas of the planet as a consequence of global warming.

The emphasis placed on the activities of mobile teams in the detection of gambiense human African trypanosomiasis (HAT) can at times obscure the major role played by fixed health facilities in HAT control and surveillance.,The lack of consistent and detailed data on the coverage of passive case-finding and treatment further constrains our ability to appreciate the full contribution of the health system to the control of HAT.,A survey was made of all fixed health facilities that are active in the control and surveillance of gambiense HAT.,Information on their diagnostic and treatment capabilities was collected, reviewed and harmonized.,Health facilities were geo-referenced.,Time-cost distance analysis was conducted to estimate physical accessibility and the potential coverage of the population at-risk of gambiense HAT.,Information provided by the National Sleeping Sickness Control Programmes revealed the existence of 632 fixed health facilities that are active in the control and surveillance of gambiense HAT in endemic countries having reported cases or having conducted active screening activities during the period 2000-2012.,Different types of diagnosis (clinical, serological, parasitological and disease staging) are available from 622 facilities.,Treatment with pentamidine for first-stage disease is provided by 495 health facilities, while for second-stage disease various types of treatment are available in 206 health facilities only.,Over 80% of the population at-risk for gambiense HAT lives within 5-hour travel of a fixed health facility offering diagnosis and treatment for the disease.,Fixed health facilities have played a crucial role in the diagnosis, treatment and coverage of at-risk-population for gambiense HAT.,As the number of reported cases continues to dwindle, their role will become increasingly important for the prospects of disease elimination.,Future updates of the database here presented will regularly provide evidence to inform and monitor a rational deployment of control and surveillance efforts.,Support to the development and, if successful, the implementation of new control tools (e.g. new diagnostics and new drugs) is crucial, both for strengthening and expanding the existing network of fixed health facilities by improving access to diagnosis and treatment and for securing a sustainable control and surveillance of gambiense HAT.

Human African trypanosomiasis (HAT) has been a major public health problem in South Sudan for the last century.,Recurrent outbreaks with a repetitive pattern of responding-scaling down activities have been observed.,Control measures for outbreak response were reduced when the prevalence decreased and/or socio-political crisis erupted, leading to a new increase in the number of cases.,This paper aims to raise international awareness of the threat of another outbreak of sleeping sickness in South Sudan.,It is a review of the available data, interventions over time, and current reports on the status of HAT in South Sudan.,Since 2006, control interventions and treatments providing services for sleeping sickness have been reduced.,Access to HAT diagnosis and treatment has been considerably diminished.,The current status of control activities for HAT in South Sudan could lead to a new outbreak of the disease unless 1) the remaining competent personnel are used to train younger staff to resume surveillance and treatment in the centers where HAT activities have stopped, and 2) control of HAT continues to be given priority even when the number of cases has been substantially reduced.,Failure to implement an effective and sustainable system for HAT control and surveillance will increase the risk of a new epidemic.,That would cause considerable suffering for the affected population and would be an impediment to the socioeconomic development of South Sudan.

Cerebral malaria (CM) causes a rapidly developing coma, and remains a major contributor to morbidity and mortality in malaria-endemic regions.,This study sought to determine the relationship between cerebrospinal fluid (CSF) Plasmodium falciparum histidine rich protein-2 (PfHRP-2) and clinical, laboratory and radiographic features in a cohort of children with retinopathy-positive CM.,Patients included in the study were admitted (2009-2013) to the Pediatric Research Ward (Queen Elizabeth Central Hospital, Blantyre, Malawi) meeting World Health Organization criteria for CM with findings of malarial retinopathy.,Enzyme-linked immunosorbent assay was used to determine plasma and CSF PfHRP-2 levels.,Wilcoxon rank-sum tests and multivariable logistic regression analysis assessed the association of clinical and radiographic characteristics with the primary outcome of death during hospitalization.,In this cohort of 94 patients, median age was 44 (interquartile range 29-62) months, 53 (56.4%) patients were male, 6 (7%) were HIV-infected, and 10 (11%) died during hospitalization.,Elevated concentrations of plasma lactate (p = 0.005) and CSF PfHRP-2 (p = 0.04) were significantly associated with death.,On multivariable analysis, higher PfHRP-2 in the CSF was associated with death (odds ratio 9.00, 95% confidence interval 1.44-56.42) while plasma PfHRP-2 was not (odds ratio 2.05, 95% confidence interval 0.45-9.35).,Elevation of CSF, but not plasma PfHRP-2, is associated with death in this paediatric CM cohort.,PfHRP-2 egress into the CSF may represent alteration of blood brain barrier permeability related to the sequestration of parasitized erythrocytes in the cerebral microvasculature.,The online version of this article (10.1186/s12936-018-2272-y) contains supplementary material, which is available to authorized users.

Adhesion interactions between Plasmodium falciparum-infected erythrocytes (IE) and human cells underlie the pathology of severe malaria.,IE cytoadhere to microvascular endothelium or form rosettes with uninfected erythrocytes to survive in vivo by sequestering IE in the microvasculature and avoiding splenic clearance mechanisms.,Both rosetting and cytoadherence are mediated by the parasite-derived IE surface protein family Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1).,Rosetting and cytoadherence have been widely studied as separate entities; however, the ability of rosetting P. falciparum strains to cytoadhere has received little attention.,Here, we show that IE of the IT/R29 strain expressing a rosette-mediating PfEMP1 variant (IT4var09) cytoadhere in vitro to a human brain microvascular endothelial cell line (HBEC-5i).,Cytoadherence was inhibited by heparin and by treatment of HBEC-5i with heparinase III, suggesting that the endothelial receptors for IE binding are heparan sulfate proteoglycans.,Antibodies to the N-terminal regions of the IT4var09 PfEMP1 variant (NTS-DBL1α and DBL2γ domains) specifically inhibited and reversed cytoadherence down to low concentrations (<10 μg/ml of total IgG).,Surface plasmon resonance experiments showed that the NTS-DBLα and DBL2γ domains bind strongly to heparin, with half-maximal binding at a concentration of ∼0.5 μM in both cases.,Therefore, cytoadherence of IT/R29 IE is distinct from rosetting, which is primarily mediated by NTS-DBL1α interactions with complement receptor 1.,These data show that IT4var09-expressing parasites are capable of dual interactions with both endothelial cells and uninfected erythrocytes via distinct receptor-ligand interactions.

Planning and evaluating malaria control strategies relies on accurate definition of parasite prevalence in the population.,A large proportion of asymptomatic parasite infections can only be identified by surveillance with molecular methods, yet these infections also contribute to onward transmission to mosquitoes.,The sensitivity of molecular detection by PCR is limited by the abundance of the target sequence in a DNA sample; thus, detection becomes imperfect at low densities.,We aimed to increase PCR diagnostic sensitivity by targeting multi-copy genomic sequences for reliable detection of low-density infections, and investigated the impact of these PCR assays on community prevalence data.,Two quantitative PCR (qPCR) assays were developed for ultra-sensitive detection of Plasmodium falciparum, targeting the high-copy telomere-associated repetitive element 2 (TARE-2, ∼250 copies/genome) and the var gene acidic terminal sequence (varATS, 59 copies/genome).,Our assays reached a limit of detection of 0.03 to 0.15 parasites/μl blood and were 10× more sensitive than standard 18S rRNA qPCR.,In a population cross-sectional study in Tanzania, 295/498 samples tested positive using ultra-sensitive assays.,Light microscopy missed 169 infections (57%).,18S rRNA qPCR failed to identify 48 infections (16%), of which 40% carried gametocytes detected by pfs25 quantitative reverse-transcription PCR.,To judge the suitability of the TARE-2 and varATS assays for high-throughput screens, their performance was tested on sample pools.,Both ultra-sensitive assays correctly detected all pools containing one low-density P. falciparum-positive sample, which went undetected by 18S rRNA qPCR, among nine negatives.,TARE-2 and varATS qPCRs improve estimates of prevalence rates, yet other infections might still remain undetected when absent in the limited blood volume sampled.,Measured malaria prevalence in communities is largely determined by the sensitivity of the diagnostic tool used.,Even when applying standard molecular diagnostics, prevalence in our study population was underestimated by 8% compared to the new assays.,Our findings highlight the need for highly sensitive tools such as TARE-2 and varATS qPCR in community surveillance and for monitoring interventions to better describe malaria epidemiology and inform malaria elimination efforts.,Ingrid Felger and colleagues developed an assay that targets multi-copy genomic sequences and can detect low-density infections with falciparum malaria parasites.,Nearly half the world's population is at risk of malaria, and more than 600,000 people die from this mosquito-borne parasitic infection every year.,Most of these deaths are caused by Plasmodium falciparum, which is transmitted to people by night-flying Anopheles mosquitoes.,These insects inject “sporozoites” into people, a parasitic form that replicates inside human liver cells.,After a few days, the liver cells release “merozoites,” which invade red blood cells, where they replicate rapidly before bursting out and infecting more red blood cells.,This increase in parasitic burden causes malaria's characteristic fever, which needs to be treated promptly to prevent anemia and organ damage.,Infected red blood cells also release “gametocytes,” which infect mosquitoes when they take a blood meal.,In the mosquito, the gametocytes multiply and develop into sporozoites, thus completing the parasite's life cycle.,Malaria can be prevented by controlling the mosquitoes that spread the parasite and by avoiding mosquito bites.,Effective treatment with antimalarial drugs also helps to reduce malaria transmission and is a key component of global efforts to control and eliminate malaria.,Planning and evaluating malaria control and elimination efforts relies on having accurate and sensitive methods to measure parasite prevalence-the proportion of a population infected with parasites.,It is particularly important to know how many people are carrying low-density infections because although these individuals have no symptoms, they contribute to malaria transmission.,In the past, malaria was usually diagnosed by looking for parasites in blood using light microscopy, but molecular tests based on “quantitative polymerase chain reactions” (qPCRs) are now available that detect much lower parasite densities in blood (submicroscopic infections). qPCRs detect parasite-specific DNA sequences in patient blood samples, but reliable detection of low-density infections remains imperfect because the abundance of target sequences in patient samples limits the sensitivity of current qPCR methods.,Here, the researchers investigate whether the sensitivity of P. falciparum detection using qPCR can be improved by targeting multi-copy genomic sequences-DNA sequences that are repeated many times in the parasite's genetic blueprint.,The researchers developed two new qPCRs for P. falciparum by using the telomere-associated repetitive element 2 (TARE-2; 250 copies/genome) and the var gene acidic terminal sequence (varATS; 59 copies/genome) as target sequences.,Direct comparison of these qPCRs with the standard 18S rRNA qPCR for P. falciparum, which targets a gene present at 5-8 copies/genome, indicated that the new assays were ten times more sensitive than the standard assay and could detect as few as 0.03-0.15 parasites/μl blood.,Next, the researchers used light microscopy, 18S rRNA qPCR, and the two new qPCRs to look for P. falciparum parasites in 498 samples randomly selected from a malaria survey undertaken in Tanzania.,Parasite prevalences were 25% by light microscopy, 50% by 18S rRNA qPCR, and 58% by TARE-2 or varATS qPCR.,Compared to TARE-2 or varATS qPCR, 18S rRNA qPCR failed to identify 48 infections (16% of infections).,Moreover, 40% of the positive samples missed by 18S rRNA qPCR contained gametocytes (detected by a different PCR-based assay) and therefore came from individuals capable of transmitting malaria parasites to mosquitoes.,Finally, to test the suitability of the new ultra-sensitive assays for use in high-throughput screens, the researchers tested performance of the assays on sample pools.,Both tests correctly identified all pools containing one low-density P. falciparum-positive sample among nine negative samples, whereas 18S rRNA qPCR identified none of these pools.,These findings provide evidence of low-density malaria infections in individuals previously thought to be parasite-free, even after testing with a molecular diagnostic.,Notably, in the population considered in this study, the standard 18S rRNA qPCR underestimated parasite prevalence by nearly 10%.,The assays developed in this study have some important limitations, however.,First, they detect only P. falciparum, and malaria control programs ideally need assays that detect all the Plasmodium species that cause malaria.,Second, because the TARE-2 and varATS qPCRs require advanced laboratory infrastructure, they cannot be used in remote field settings.,Nevertheless, because low-density infections are likely to become increasingly common as countries improve malaria control, these findings highlight the need for ultra-sensitive tools such as the TARE-2 and varATS qPCRs for community surveillance and for monitoring the progress of malaria control and elimination programs.,Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001788.,Information is available from the World Health Organization on malaria (in several languages), including information on malaria diagnosis; the World Malaria Report 2014 provides details of the current global malaria situation,The US Centers for Disease Control and Prevention also provides information on all aspects of malaria; its website provides a selection of personal stories about malaria,Information is available from the Roll Back Malaria Partnership on the global control of malaria and on the Global Malaria Action Plan (in English and French),MedlinePlus provides links to additional information on malaria (in English and Spanish)

RTS,S is the most advanced malaria vaccine candidate, currently under phase-III clinical trials in Africa.,This Plasmodium falciparum vaccine contains part of the central repeat region and the complete C-terminal T cell epitope region (Th2R and Th3R) of the circumsporozoite protein (CSP).,Since naturally occurring polymorphisms at the vaccine candidate loci are critical determinants of the protective efficacy of the vaccines, it is imperative to investigate these polymorphisms in field isolates.,In this study we have investigated the genetic diversity at the central repeat, C-terminal T cell epitope (Th2R and Th3R) and N-terminal T cell epitope regions of the CSP, in P. falciparum isolates from Madhya Pradesh state of India.,These isolates were collected through a 5-year prospective study aimed to develop a well-characterized field-site for the future evaluation of malaria vaccine in India.,Our results revealed that the central repeat (63 haplotypes, n = 161) and C-terminal Th2R/Th3R epitope (24 haplotypes, n = 179) regions were highly polymorphic, whereas N-terminal non-repeat region was less polymorphic (5 haplotypes, n = 161) in this population.,We did not find any evidence of the role of positive natural selection in maintaining the genetic diversity at the Th2R/Th3R regions of CSP.,Comparative analysis of the Th2R/Th3R sequences from this study to the global isolates (n = 1160) retrieved from the GenBank database revealed two important points.,First, the majority of the sequences (∼61%, n = 179) from this study were identical to the Dd2/Indochina type, which is also the predominant Th2R/Th3R haplotype in Asia (∼59%, n = 974).,Second, the Th2R/Th3R sequences in Asia, South America and Africa are geographically distinct with little allele sharing between continents.,In conclusion, this study provides an insight on the existing polymorphisms in the CSP in a parasite population from India that could potentially influence the efficacy of RTS,S vaccine in this region.

Loop-mediated isothermal amplification (LAMP) is a rapid and sensitive tool used for the diagnosis of a variety of infectious diseases.,One of the advantages of this method over the polymerase chain reaction is that DNA amplification occurs at a constant temperature, usually between 60-65°C; therefore, expensive devices are unnecessary for this step.,However, LAMP still requires complicated sample preparation steps and a well-equipped laboratory to produce reliable and reproducible results, which limits its use in resource-poor laboratories in most developing countries.,In this study, we made several substantial modifications to the technique to carry out on-site diagnosis of Human African Trypanosomiasis (HAT) in remote areas using LAMP.,The first essential improvement was that LAMP reagents were dried and stabilized in a single tube by incorporating trehalose as a cryoprotectant to prolong shelf life at ambient temperature.,The second technical improvement was achieved by simplifying the sample preparation step so that DNA or RNA could be amplified directly from detergent-lysed blood samples.,With these modifications, diagnosis of HAT in local clinics or villages in endemic areas becomes a reality, which could greatly impact on the application of diagnosis not only for HAT but also for other tropical diseases.

The analytical validation of sensitive, accurate and standardized Real-Time PCR methods for Trypanosoma cruzi quantification is crucial to provide a reliable laboratory tool for diagnosis of recent infections as well as for monitoring treatment efficacy.,We have standardized and validated a multiplex Real-Time quantitative PCR assay (qPCR) based on TaqMan technology, aiming to quantify T. cruzi satellite DNA as well as an internal amplification control (IAC) in a single-tube reaction.,IAC amplification allows rule out false negative PCR results due to inhibitory substances or loss of DNA during sample processing.,The assay has a limit of detection (LOD) of 0.70 parasite equivalents/mL and a limit of quantification (LOQ) of 1.53 parasite equivalents/mL starting from non-boiled Guanidine EDTA blood spiked with T. cruzi CL-Brener stock.,The method was evaluated with blood samples collected from Chagas disease patients experiencing different clinical stages and epidemiological scenarios: 1- Sixteen Venezuelan patients from an outbreak of oral transmission, 2- Sixty three Bolivian patients suffering chronic Chagas disease, 3- Thirty four Argentinean cases with chronic Chagas disease, 4- Twenty seven newborns to seropositive mothers, 5- A seronegative receptor who got infected after transplantation with a cadaveric kidney explanted from an infected subject.,The performing parameters of this assay encourage its application to early assessment of T. cruzi infection in cases in which serological methods are not informative, such as recent infections by oral contamination or congenital transmission or after transplantation with organs from seropositive donors, as well as for monitoring Chagas disease patients under etiological treatment.

microRNAs (miRNAs), a class of short, non-coding RNA can be found in a highly stable, cell-free form in mammalian body fluids.,Specific miRNAs are secreted by parasitic nematodes in exosomes and have been detected in the serum of murine and dog hosts infected with the filarial nematodes Litomosoides sigmodontis and Dirofilaria immitis, respectively.,Here we identify extracellular, parasite-derived small RNAs associated with Onchocerca species infecting cattle and humans.,Small RNA libraries were prepared from total RNA extracted from the nodule fluid of cattle infected with Onchocerca ochengi as well as serum and plasma from humans infected with Onchocerca volvulus in Cameroon and Ghana.,Parasite-derived miRNAs were identified based on the criteria that sequences unambiguously map to hairpin structures in Onchocerca genomes, do not align to the human genome and are not present in European control serum.,A total of 62 mature miRNAs from 52 distinct pre-miRNA candidates were identified in nodule fluid from cattle infected with O. ochengi of which 59 are identical in the genome of the human parasite O. volvulus.,Six of the extracellular miRNAs were also identified in sequencing analyses of serum and plasma from humans infected with O. volvulus.,Based on sequencing analysis the abundance levels of the parasite miRNAs in serum or plasma range from 5 to 127 reads/per million total host miRNA reads identified, comparable to our previous analyses of Schistosoma mansoni and L. sigmodontis miRNAs in serum.,All six of the O. volvulus miRNAs identified have orthologs in other filarial nematodes and four were identified in the serum of mice infected with L. sigmodontis.,We have identified parasite-derived miRNAs associated with onchocerciasis in cattle and humans.,Our results confirm the conserved nature of RNA secretion by diverse nematodes.,Additional species-specific small RNAs from O. volvulus may be present in serum based on the novel miRNA sequences identified in the nodule fluid.,In our analyses comparison to European control serum illuminates the scope for false-positives, warranting caution in criteria that should be applied to identification of biomarkers of infection.,The online version of this article (doi:10.1186/s13071-015-0656-1) contains supplementary material, which is available to authorized users.

Cerebral malaria (CM) and severe anemia (SA) are the most severe complications of Plasmodium falciparum infections.,Although increased release of endothelial microparticles (MP) correlates with malaria severity, the full extent of vascular cell vesiculation remains unknown.,Here, we characterize the pattern of cell-specific MP in patients with severe malaria.,We tested the hypothesis that systemic vascular activation contributes to CM by examining origins and levels of plasma MP in relation to clinical syndromes, disease severity and outcome.,Patients recruited in Douala, Cameroon, were assigned to clinical groups following WHO criteria.,MP quantitation and phenotyping were carried out using cell-specific markers by flow cytometry using antibodies recognizing cell-specific surface markers.,Platelet, erythrocytic, endothelial and leukocytic MP levels were elevated in patients with cerebral dysfunctions and returned to normal by discharge.,In CM patients, platelet MP were the most abundant and their levels significantly correlated with coma depth and thrombocytopenia.,This study shows for the first time a widespread enhancement of vesiculation in the vascular compartment appears to be a feature of CM but not of SA.,Our data underpin the role of MP as a biomarker of neurological involvement in severe malaria.,Therefore, intervention to block MP production in severe malaria may provide a new therapeutic pathway.

To reduce the risk of drug-induced haemolysis, all patients should be tested for glucose-6-phosphate dehydrogenase (G6PD) deficiency (G6PDd) prior to prescribing primaquine (PQ)-based radical cure for the treatment of vivax malaria.,This systematic review and individual patient meta-analysis assessed the utility of a qualitative lateral flow assay from Access Bio/CareStart (Somerset, NJ) (CareStart Screening test for G6PD deficiency) for the diagnosis of G6PDd compared to the gold standard spectrophotometry (International Prospective Register of Systematic Reviews [PROSPERO]: CRD42019110994).,Articles published on PubMed between 1 January 2011 and 27 September 2019 were screened.,Articles reporting performance of the standard CSG from venous or capillary blood samples collected prospectively and considering spectrophotometry as gold standard (using kits from Trinity Biotech PLC, Wicklow, Ireland) were included.,Authors of articles fulfilling the inclusion criteria were contacted to contribute anonymized individual data.,Minimal data requested were sex of the participant, CSG result, spectrophotometry result in U/gHb, and haemoglobin (Hb) reading.,The adjusted male median (AMM) was calculated per site and defined as 100% G6PD activity.,G6PDd was defined as an enzyme activity of less than 30%.,Pooled estimates for sensitivity and specificity, unconditional negative predictive value (NPV), positive likelihood ratio (LR+), and negative likelihood ratio (LR−) were calculated comparing CSG results to spectrophotometry using a random-effects bivariate model.,Of 11 eligible published articles, individual data were available from 8 studies, 6 from Southeast Asia, 1 from Africa, and 1 from the Americas.,A total of 5,815 individual participant data (IPD) were available, of which 5,777 results (99.3%) were considered for analysis, including data from 3,095 (53.6%) females.,Overall, the CSG had a pooled sensitivity of 0.96 (95% CI 0.90-0.99) and a specificity of 0.95 (95% CI 0.92-0.96).,When the prevalence of G6PDd was varied from 5% to 30%, the unconditional NPV was 0.99 (95% CI 0.94-1.00), with an LR+ and an LR− of 18.23 (95% CI 13.04-25.48) and 0.05 (95% CI 0.02-0.12), respectively.,Performance was significantly better in males compared to females (p = 0.027) but did not differ significantly between samples collected from capillary or venous blood (p = 0.547).,Limitations of the study include the lack of wide geographical representation of the included data and that the CSG results were generated under research conditions, and therefore may not reflect performance in routine settings.,The CSG performed well at the 30% threshold.,Its high NPV suggests that the test is suitable to guide PQ treatment, and the high LR+ and low LR− render the test suitable to confirm and exclude G6PDd.,Further operational studies are needed to confirm the utility of the test in remote endemic settings.,In this systematic review and meta-analysis, Benedikt Ley and colleagues assess the performance of a point of care screening test for identifyint vivax malaria patients who are at risk of drug-induced haemolysis.

Treatment of Plasmodium vivax malaria requires the clearing of asexual parasites, but relapse can be prevented only if dormant hypnozoites are cleared from the liver (a treatment termed “radical cure”).,Tafenoquine is a single-dose 8-aminoquinoline that has recently been registered for the radical cure of P. vivax.,This multicenter, double-blind, double-dummy, parallel group, randomized, placebo-controlled trial was conducted in Ethiopia, Peru, Brazil, Cambodia, Thailand, and the Philippines.,We enrolled 522 patients with microscopically confirmed P. vivax infection (>100 to <100,000 parasites per microliter) and normal glucose-6-phosphate dehydrogenase (G6PD) activity (with normal activity defined as ≥70% of the median value determined at each trial site among 36 healthy male volunteers who were otherwise not involved in the trial).,All patients received a 3-day course of chloroquine (total dose of 1500 mg).,In addition, patients were assigned to receive a single 300-mg dose of tafenoquine on day 1 or 2 (260 patients), placebo (133 patients), or a 15-mg dose of prima-quine once daily for 14 days (129 patients).,The primary outcome was the Kaplan- Meier estimated percentage of patients who were free from recurrence at 6 months, defined as P. vivax clearance without recurrent parasitemia.,In the intention-to-treat population, the percentage of patients who were free from recurrence at 6 months was 62.4% in the tafenoquine group (95% confidence interval [CI], 54.9 to 69.0), 27.7% in the placebo group (95% CI, 19.6 to 36.6), and 69.6% in the primaquine group (95% CI, 60.2 to 77.1).,The hazard ratio for the risk of recurrence was 0.30 (95% CI, 0.22 to 0.40) with tafenoquine as compared with placebo (P<0.001) and 0.26 (95% CI, 0.18 to 0.39) with primaquine as compared with placebo (P<0.001).,Tafenoquine was associated with asymptomatic declines in hemoglobin levels, which resolved without intervention.,Single-dose tafenoquine resulted in a significantly lower risk of P. vivax recurrence than placebo in patients with phenotypically normal G6PD activity.,(Funded by GlaxoSmith-Kline and Medicines for Malaria Venture; DETECTIVE ClinicalTrials.gov number, NCT01376167.)

LLINs containing an insecticide plus the synergist, piperonyl butoxide (PBO) have been designed for increased efficacy against pyrethroid-resistant malaria vectors.,In this study, two LLINs with PBO, PermaNet® 3.0 and Olyset® Plus, and a pyrethroid-only LLIN, Yorkool®, were evaluated in experimental huts against a free-flying, wild population of Anopheles gambiae s.l. in Kolokopé, a cotton cultivated area of Togo.,WHO susceptibility tube tests and subsequent molecular assays determine the An. gambiae s.l. populations to be resistant to pyrethroids and DDT with both target site kdr and metabolic resistance mechanisms involved in the resistance observed.,Anopheles gambiae s.s. and An. coluzzi were present in sympatry though the kdr (L1014F) mutation was observed at a higher frequency in An. gambiae s.s.,The experimental hut results showed that both PermaNet® 3.0 and Olyset® Plus nets induced similar levels of deterrence, exophily, and reduced blood feeding rate against wild An. gambiae s.l. in contrast to the pyrethroid only LLIN, Yorkool®.,The proportion of wild An. gambiae s.l. killed by unwashed PermaNet® 3.0 was significantly higher than unwashed Olyset® Plus (corrected mortality 80.5% compared to 66.6%).,Similar blood feeding inhibition rates were observed for unwashed PermaNet® 3.0 and Olyset® Plus; however, PermaNet® 3.0 washed 20 times demonstrated significantly higher blood feeding inhibition rate than Olyset® Plus washed 20 times (91.1% compared with 85.6% respectively).,Yorkool® performed the worst for all the parameters evaluated.,In an area of pyrethroid resistance of An. gambiae s.l involving kdr target site and metabolic resistance mechanisms, LLINs with PBO can provide additional protection in terms of reduction in blood feeding and increase in mosquito mortality compared to a pyrethroid-only net, and should be considered in malaria vector control strategies.

Long-lasting insecticide-treated nets (LLINs) are one of the main methods used for controlling malaria transmission in Mozambique.,The proliferation of several types of LLINs and the re-emergence of insecticide resistance in the local vector populations poses challenges to the local malaria control programme on selecting suitable insecticide-based vector control products.,Therefore, this study evaluated the insecticide susceptibility and bio-efficacy of selected new LLINs against wild populations of Anopheles funestus sensu lato and A. gambiae s.l. from Northern and Central Mozambique.,The study also investigated whether the insecticide contents on the LINNs fabrics were within the WHOPES recommended target range.,The susceptibility of 2-5 day old wild female A. funestus and A. gambiae sensu stricto against the major classes of insecticides used for vector control, viz: deltamethrin (0.05 %), permethrin (0.75 %), propoxur (0.1 %), bendiocarb (0.1 %) and DDT (4 %), was determined using WHO cylinder susceptibility tests.,WHO cone bioassays were conducted to determine the bio-efficacy of both pyrethroid-only LLINs (Olyset®, Permanet 2.0®, NetProtect® and Interceptor®) and, Permanet 3.0® a combination LLIN against A. funestus s.s, from Balama, Mocuba and Milange districts, respectively.,The bio-efficacy of LLINs against the insectary-susceptible A. arabiensis (Durban strain) was assessed, as well.,Untreated bed net swatches were used as negative controls.,Chemical analyses, by high performance liquid chromatography, were undertaken to assess whether the insecticide contents on the LLINs fabrics fell within recommended target dose ranges.,The frequency of kdr gene mutations was determined from a random sample of A. gambiaes.s. from both WHO susceptibility and cone bioassay experiments.,Anopheles funestus from Balama district showed resistance to deltamethrin and possible resistance to permethrin, propoxur and bendiocarb, whilst A. gambiae from Mocuba district was susceptible to deltamethrin, bendiocarb and propoxur.,There were no kdr mutants found in the sample of 256 A. gambiae tested.,Overall, 186 LLIN swatches were tested.,Mosquitoes exposed to Olyset® had the lowest knockdown (±standard error) and mortality rate (±standard error) in all studied sites regardless of vectors species tested.,Permanet 3.0 showed the highest bio-efficacy independent of vector species tested and level of insecticide resistance detected.,All types of LLINs effectively killed susceptible A. arabiensis Durban strain.,The insecticide content of Olyset® and Permanet 2.0® was higher than the target dose but NetProtect® had a lower insecticide content than the target dose.,The study shows evidence of considerable heterogeneity in both insecticide susceptibility and the level of bio-efficacy of commonly available types of LLINs against wild A. funestus and A. gambiae from Balama, Mocuba and Milange districts, located in north and centre of Mozambique.,The findings suggest that vector control approaches combining different types of insecticides might help to tackle the apparent problem of pyrethroid resistance in the vector populations from these three sites.,Results from bioassays on laboratory-susceptible A. arabiensis strongly suggest that LLINs can offer some protection against susceptible malaria vectors.,The online version of this article (doi:10.1186/s12936-015-0885-y) contains supplementary material, which is available to authorized users.

Adults are frequently infected with malaria and may serve as a reservoir for further transmission, yet we know relatively little about risk factors for adult infections.,In this study, we assessed malaria risk factors among adults using samples from the nationally representative, cross-sectional 2013-2014 Demographic and Health Survey (DHS) conducted in the Democratic Republic of the Congo (DRC).,We further explored differences in risk factors by urbanicity.,Plasmodium falciparum infection was determined by PCR.,Covariates were drawn from the DHS to model individual, community and environmental-level risk factors for infection.,Additionally, we used deep sequencing data to estimate the community-level proportions of drug-resistant infections and included these estimates as potential risk factors.,All identified factors were assessed for differences in associations by urbanicity.,A total of 16 126 adults were included.,Overall prevalence of malaria was 30.3% (SE=1.1) by PCR; province-level prevalence ranged from 6.7% to 58.3%.,Only 17% of individuals lived in households with at least one bed-net for every two people, as recommended by the WHO.,Protective factors included increasing within-household bed-net coverage (Prevalence Ratio=0.85, 95% CI=0.76-0.95) and modern housing (PR=0.58, 95% CI=0.49-0.69).,Community-level protective factors included increased median wealth (PR=0.87, 95% CI=0.83-0.92).,Education, wealth, and modern housing showed protective associations in cities but not in rural areas.,The DRC continues to suffer from a high burden of malaria; interventions that target high-risk groups and sustained investment in malaria control are sorely needed.,Areas of high prevalence should be prioritised for interventions to target the largest reservoirs for further transmission.

The private sector supplies anti-malarial treatment for large proportions of patients in sub-Saharan Africa.,Following the large-scale piloting of the Affordable Medicines Facility-malaria (AMFm) from 2010 to 2011, a private sector co-payment mechanism (CPM) provided continuation of private sector subsidies for quality-assured artemisinin combination therapies (QAACT).,This article analyses for the first time the extent to which improvements in private sector QAACT supply and distribution observed during the AMFm were maintained or intensified during continuation of the CPM through 2015 in Kenya, Madagascar, Nigeria, Tanzania and Uganda using repeat cross-sectional outlet survey data.,QAACT market share in all five countries increased during the AMFm period (p < 0.001).,According to the data from the last ACTwatch survey round, in all study countries except Madagascar, AMFm levels of private sector QAACT availability were maintained or improved.,In 2014/15, private sector QAACT availability was greater than 70% in Nigeria (84.3%), Kenya (70.5%), Tanzania (83.0%) and Uganda (77.1%), but only 11.2% in Madagascar.,QAACT market share was maintained or improved post-AMFm in Nigeria, Tanzania and Uganda, but statistically significant declines were observed in Kenya and Madagascar.,In 2014/5, QAACT market share was highest in Kenya and Uganda (48.2 and 47.5%, respectively) followed by Tanzania (39.2%), Nigeria (35.0%), and Madagascar (7.0%).,Four of the five countries experienced significant decreases in median QAACT price during the AMFm period.,Private sector QAACT prices were maintained or further reduced in Tanzania, Nigeria and Uganda, but prices increased significantly in Kenya and Madagascar.,SP prices were consistently lower than those of QAACT in the AMFm period, with the exception of Kenya and Tanzania in 2011, where they were equal.,In 2014/5 QAACT remained two to three times more expensive than the most popular non-artemisinin therapy in all countries except Tanzania.,Results suggest that a private sector co-payment mechanism for QAACT implemented at national scale for 5 years was associated with positive and sustained improvements in QAACT availability, price and market share in Nigeria, Tanzania and Uganda, with more mixed results in Kenya, and few improvements in Madagascar.,The subsidy mechanism as implemented over time across countries was not sufficient on its own to achieve optimal QAACT uptake.,Supporting interventions to address continued availability and distribution of non-artemisinin therapies, and to create demand for QAACT among providers and consumers need to be effectively implemented to realize the full potential of this subsidy mechanism.,Furthermore, there is need for comprehensive market assessments to identify contemporary market barriers to high coverage with both confirmatory testing and appropriate treatment.,The online version of this article (doi:10.1186/s12936-017-1814-z) contains supplementary material, which is available to authorized users.

Loop-mediated isothermal DNA amplification (LAMP) methodology offers an opportunity for point-of-care (POC) molecular detection of asymptomatic malaria infections.,However, there is still little evidence on the feasibility of implementing this technique for population screenings in isolated field settings.,Overall, we recruited 1167 individuals from terrestrial (‘road’) and hydric (‘riverine’) communities of the Peruvian Amazon for a cross-sectional survey to detect asymptomatic malaria infections.,The technical performance of LAMP was evaluated in a subgroup of 503 samples, using real-time Polymerase Chain Reaction (qPCR) as reference standard.,The operational feasibility of introducing LAMP testing in the mobile screening campaigns was assessed based on field-suitability parameters, along with a pilot POC-LAMP assay in a riverine community without laboratory infrastructure.,LAMP had a sensitivity of 91.8% (87.7-94.9) and specificity of 91.9% (87.8-95.0), and the overall accuracy was significantly better among samples collected during road screenings than riverine communities (p≤0.004).,LAMP-based diagnostic strategy was successfully implemented within the field-team logistics and the POC-LAMP pilot in the riverine community allowed for a reduction in the turnaround time for case management, from 12-24 hours to less than 5 hours.,Specimens with haemolytic appearance were regularly observed in riverine screenings and could help explaining the hindered performance/interpretation of the LAMP reaction in these communities.,LAMP-based molecular malaria diagnosis can be deployed outside of reference laboratories, providing similar performance as qPCR.,However, scale-up in remote field settings such as riverine communities needs to consider a number of logistical challenges (e.g. environmental conditions, labour-intensiveness in large population screenings) that can influence its optimal implementation.

The malaria rapid diagnostic tests (RDTs) are now widely used in the world.,Compared to Plasmodium falciparum, a poor sensitivity of RDTs was reported against Plasmodium vivax based on the adopted antibody against pan-Plasmodium antigen lactate dehydrogenase (pLDH) or aldolase.,Levels of pLDH were measured from patient with P. vivax, and the correlations between the levels of pLDH and the sensitivities of RDTs were analysed among Republic of Korea (ROK) isolates.,Three RDTs, OptiMAL test, SD BIOLINE Malaria Ag P.f/Pan test, Humasis Malaria Pf/Pan antigen test, and the Genedia pLDH antigen ELISA were performed with blood samples from 152 febrile patients and 100 healthy controls.,Three malaria RDTs revealed sensitivities between 85.5 (131/152) and 86.8% (132/152) with highest sensitivity for the detection of P.vivax by pLDH antigen ELISA test (145/152, 95.4%) in comparison to traditional microscopy using Giemsa-stained slides.,None of the healthy control tested positive by three RDTs or ELISA, indicating 100% specificity in their respective test.,Levels of pLDH among Korean P. vivax isolates ranged between 0 ng/mL and 22,387.2 ng/mL (mean ± standard deviation 3,917.5 ± 6,120.9 ng/mL).,The lower detection limits of three RDTs were between 25 and 50 ng/mL with artificially diluted samples.,The moderate degree of correlation was observed between parasitaemia and concentrations of pLDH (r = 0.4, p < 0.05).,The pLDH levels of P. vivax are the main explanation for the variations in the performance of pLDH-based RDTs.,Therefore, comparing sensitivities of RDT may need to include targeted biomarker value of patients.

Tick-borne encephalitis (TBE) is one tick-transmitted disease where the human incidence has increased in some European regions during the last two decades.,We aim to find the most important factors causing the increasing incidence of human TBE in Sweden.,Based on a review of published data we presume that certain temperature-related variables and the population densities of transmission hosts, i.e. small mammals, and of primary tick maintenance hosts, i.e. cervids and lagomorphs, of the TBE virus vector Ixodes ricinus, are among the potentially most important factors affecting the TBE incidence.,Therefore, we compare hunting data of the major tick maintenance hosts and two of their important predators, and four climatic variables with the annual numbers of human cases of neuroinvasive TBE.,Data for six Swedish regions where human TBE incidence is high or has recently increased are examined by a time-series analysis.,Results from the six regions are combined using a meta-analytical method.,With a one-year time lag, the roe deer (Capreolus capreolus), red deer (Cervus elaphus), mountain hare (Lepus timidus) and European hare (Lepus europaeus) showed positive covariance; the Eurasian elk (moose, Alces alces) and fallow deer (Dama dama) negative covariance; whereas the wild boar (Sus scrofa), lynx (Lynx lynx), red fox (Vulpes vulpes) and the four climate parameters showed no significant covariance with TBE incidence.,All game species combined showed positive covariance.,The epidemiology of TBE varies with time and geography and depends on numerous factors, i.a. climate, virus genotypes, and densities of vectors, tick maintenance hosts and transmission hosts.,This study suggests that the increased availability of deer to I. ricinus over large areas of potential tick habitats in southern Sweden increased the density and range of I. ricinus and created new TBEV foci, which resulted in increased incidence of human TBE.,New foci may be established by TBE virus-infected birds, or by birds or migrating mammals infested with TBEV-infected ticks.,Generally, persistence of TBE virus foci appears to require presence of transmission-competent small mammals, especially mice (Apodemus spp.) or bank voles (Myodes glareolus).,The online version of this article (10.1186/s13071-018-3057-4) contains supplementary material, which is available to authorized users.

Ticks and tick-borne diseases are increasing in many areas of Europe and North America due to climate change, while land use and the increased abundances of large hosts play a more controversial role.,The pattern of host selection involves a crucial component for tick abundance.,While the larvae and nymphs feed on a wide range of different sized hosts, the adult female ticks require blood meal from a large host (>1 kg), typically a deer, to fulfil the life cycle.,Understanding the role of different hosts for abundances of ticks is therefore important, and also the extent to which different life stages attach to large hosts.,We studied attachment site selection of life stages of I. ricinus ticks on a main large host in Europe, the red deer (Cervus elaphus).,We collected from 33 felled red deer pieces of skin from five body parts: leg, groin, neck, back and ear.,We counted the number of larval, nymphal, adult male and adult female ticks.,Nymphs (42.2%) and adult (48.7%) ticks dominated over larvae (9.1%).,There were more larvae on the legs (40.9%), more nymphs on the ears (83.7%), while adults dominated in the groins (89.2%) and neck (94.9%).,Large mammalian hosts are thus a diverse habitat suitable for different life stages of ticks.,The attachment site selection reflected the life stages differing ability to move.,The spatial separation of life stages may partly limit the role of deer in co-feeding transmission cycles.

Increased insecticide-treated net (ITN) use over the last decade has contributed to dramatic declines in malaria transmission and mortality, yet residual transmission persists even where ITN coverage exceeds 80%.,This article presents observational data suggesting that complex human net use patterns, including multiple entries to and exits from ITNs by multiple occupants throughout the night, might be a contributing factor.,The study included dusk-to-dawn observations of bed net use in 60 households in the Peruvian Amazon.,Observers recorded number of net occupants and the time and number of times each occupant entered and exited each net.,The study team then tabulated time of first entry, total times each net was lifted, and, where possible, minutes spent outside by each occupant.,The sample included 446 individuals and 171 observed sleeping spaces with nets.,Household size ranged from 2 to 24 occupants; occupants per net ranged from 1 to 5.,Nets were lifted a mean 6.1 times per night (SD 4.35, range 1-22).,Observers captured substantial detail about time of and reasons for net entry and exit as well as length of time and activities undertaken outside.,These findings suggest that the ITN use patterns observed in this study may contribute to residual transmission.,As a result, respondents to net use surveys may truthfully report that they slept under a net the previous night but may not have received the anticipated protection.,More research is warranted to explore the impact of this phenomenon.,Concurrent entomological data would help assess the magnitude of the effect.

Measurement of densities of host-seeking malaria vectors is important for estimating levels of disease transmission, for appropriately allocating interventions, and for quantifying their impact.,The gold standard for estimating mosquito-human contact rates is the human landing catch (HLC), where human volunteers catch mosquitoes that land on their exposed body parts.,This approach necessitates exposure to potentially infectious mosquitoes, and is very labour intensive.,There are several safer and less labour-intensive methods, with Centers for Disease Control light traps (LT) placed indoors near occupied bed nets being the most widely used.,This paper presents analyses of 13 studies with paired mosquito collections of LT and HLC to evaluate these methods for their consistency in sampling indoor-feeding mosquitoes belonging to the two major taxa of malaria vectors across Africa, the Anopheles gambiae sensu lato complex and the Anopheles funestus s.l. group.,Both overall and study-specific sampling efficiencies of LT compared with HLC were computed, and regression methods that allow for the substantial variations in mosquito counts made by either method were used to test whether the sampling efficacy varies with mosquito density.,Generally, LT were able to collect similar numbers of mosquitoes to the HLC indoors, although the relative sampling efficacy, measured by the ratio of LT:HLC varied considerably between studies.,The overall best estimate for An. gambiae s.l. was 1.06 (95% credible interval: 0.68-1.64) and for An. funestus s.l. was 1.37 (0.70-2.68).,Local calibration exercises are not reproducible, since only in a few studies did LT sample proportionally to HLC, and there was no geographical pattern or consistent trend with average density in the tendency for LT to either under- or over-sample.,LT are a crude tool at best, but are relatively easy to deploy on a large scale.,Spatial and temporal variation in mosquito densities and human malaria transmission exposure span several orders of magnitude, compared to which the inconsistencies of LT are relatively small.,LT, therefore, remain an invaluable and safe alternative to HLC for measuring indoor malaria transmission exposure in Africa.,The online version of this article (doi:10.1186/s12936-015-0761-9) contains supplementary material, which is available to authorized users.

Haemoglobinuria is an uncommon complication of severe malaria, reflecting acute intravascular haemolysis and potentially leading to acute kidney injury.,It can occur early in the course of infection as a consequence of a high parasite burden, or may occur following commencement of anti-malarial treatment.,Treatment with quinine has been described as a risk factor; however the syndrome may also occur following treatment with intravenous artesunate.,In Malaysia, Plasmodium knowlesi is the most common cause of severe malaria, often associated with high parasitaemia.,Asplenic patients may be at additional increased risk of intravascular haemolysis.,A 61 years old asplenic man was admitted to a tertiary referral hospital in Sabah, Malaysia, with severe knowlesi malaria characterized by hyperparasitaemia (7.9 %), jaundice, respiratory distress, metabolic acidosis, and acute kidney injury.,He was commenced on intravenous artesunate, but1 day later developed haemoglobinuria, associated with a 22 % reduction in admission haemoglobin.,Additional investigations, including a cell-free haemoglobin of 10.2 × 105 ng/mL and an undetectable haptoglobin, confirmed intravascular haemolysis.,The patient continued on intravenous artesunate for a total of 48 h prior to substitution with artemether-lumefantrine, and made a good recovery with resolution of his haemoglobinuria and improvement of his kidney function by day 3.,An asplenic patient with hyperparasitaemic severe knowlesi malaria developed haemoglobinuria after treatment with intravenous artesunate.,There are plausible mechanisms for increased haemolysis with hyperparasitaemia, and following both splenectomy and artesunate.,Although in this case the patient made a rapid recovery, knowlesi malaria patients with this unusual complication should be closely monitored for potential deterioration.

The mechanism of massive intravascular haemolysis occurring during the treatment of malaria infection resulting in haemoglobinuria, commonly known as blackwater fever (BWF), remains unknown.,BWF is most often seen in those with severe malaria treated with amino-alcohol drugs, including quinine, mefloquine and halofantrine.,The potential for drugs containing artemisinins, chloroquine or piperaquine to cause oxidant haemolysis is believed to be much lower, particularly during treatment of uncomplicated malaria.,Here is an unusual case of BWF, which developed on day 2 of treatment for uncomplicated Plasmodium falciparum infection with dihydroartemisinin-piperaquine (DHA-PIP) with documented evidence of concomitant seropositivity for Chikungunya infection.

Vivax malaria was successfully eliminated from the Republic of Korea (ROK) in the late 1970s but re-emerged in 1993.,Two decades later as the ROK enters the final stages of malaria elimination, dedicated surveillance of the local P. vivax population is critical.,We apply a population genetic approach to gauge P. vivax transmission dynamics in the ROK between 2010 and 2012.,P. vivax positive blood samples from 98 autochthonous cases were collected from patients attending health centers in the ROK in 2010 (n = 27), 2011 (n = 48) and 2012 (n = 23).,Parasite genotyping was undertaken at 9 tandem repeat markers.,Although not reaching significance, a trend of increasing population diversity was observed from 2010 (HE = 0.50 ± 0.11) to 2011 (HE = 0.56 ± 0.08) and 2012 (HE = 0.60 ± 0.06).,Conversely, linkage disequilibrium declined during the same period: IAS = 0.15 in 2010 (P = 0.010), 0.09 in 2011 (P = 0.010) and 0.05 in 2012 (P = 0.010).,In combination with data from other ROK studies undertaken between 1994 and 2007, our results are consistent with increasing parasite divergence since re-emergence.,Polyclonal infections were rare (3% infections) suggesting that local out-crossing alone was unlikely to explain the increased divergence.,Cases introduced from an external reservoir may therefore have contributed to the increased diversity.,Aside from one isolate, all infections carried a short MS20 allele (142 or 149 bp), not observed in other studies in tropical endemic countries despite high diversity, inferring that these regions are unlikely reservoirs.,Whilst a number of factors may explain the observed population genetic trends, the available evidence suggests that an external geographic reservoir with moderate diversity sustains the majority of P. vivax infection in the ROK, with important implications for malaria elimination.

Malaria control efforts have a significant impact on the epidemiology and parasite population dynamics.,In countries aiming for malaria elimination, malaria transmission may be restricted to limited transmission hot spots, where parasite populations may be isolated from each other and experience different selection forces.,Here we aim to examine the Plasmodium vivax population divergence in geographically isolated transmission zones in Thailand.,We employed the P. vivax merozoite surface protein 3β (PvMSP3β) as a molecular marker for characterizing P. vivax populations based on the extensive diversity of this gene in Southeast Asian parasite populations.,To examine two parasite populations with different transmission levels in Thailand, we obtained 45 P. vivax isolates from Tak Province, northwestern Thailand, where the annual parasite incidence (API) was more than 2%, and 28 isolates from Yala and Narathiwat Provinces, southern Thailand, where the API was less than 0.02%.,We sequenced the PvMSP3β gene and examined its genetic diversity and molecular evolution between the parasite populations.,Of 58 isolates containing single PvMSP3β alleles, 31 sequence types were identified.,The overall haplotype diversity was 0.77±0.06 and nucleotide diversity 0.0877±0.0054.,The northwestern vivax malaria population exhibited extensive haplotype diversity (HD) of PvMSP3β (HD = 1.0).,In contrast, the southern parasite population displayed a single PvMSP3β allele (HD = 0), suggesting a clonal population expansion.,This result revealed that the extent of allelic diversity in P. vivax populations in Thailand varies among endemic areas.,Malaria parasite populations in a given region may vary significantly in genetic diversity, which may be the result of control and influenced by the magnitude of malaria transmission intensity.,This is an issue that should be taken into account for the implementation of P. vivax control measures such as drug policy and vaccine development.

Severe chronic hepatic schistosomiasis is a common cause of episodes upper gastrointestinal bleeding (UGIB) in sub-Saharan Africa (SSA).,However, there is paucity of data on clinical epidemiology of episodes of UGIB from rural Africa despite on going public health interventions to control and eliminate schistosomiasis.,Through a cross sectional study we profiled lifetime episodes of upper gastrointestinal bleeding and associated factors at a rural primary health facility in sub-Saharan Africa were schistosomiasis is endemic.,The main outcome was number of lifetime episodes of UGIB analyzed as count data.,From 107 enrolled participants, 323 lifetime episodes of UGIB were reported.,Fifty-seven percent experienced ≥ 2 lifetime episodes of UGIB.,Ninety-four percent had severe chronic hepatic schistosomiasis and 80% esophageal varices.,Alcohol use and viral hepatitis was infrequent.,Eighty-eight percent were previously treated with praziquantel and 70% had a history of blood transfusion.,No patient had ever had an endoscopy or treatment for prevention of recurrent variceal bleeding.,Multivariable analysis identified a cluster of eight clinical factor variables (age ≥ 40, female sex, history of blood transfusion, abdominal collaterals, esophageal varices, pattern x periportal fibrosis, anemia, and thrombocytopenia) significantly associated (P-value < 0.05) with increased probability of experiencing two or more lifetime episodes of UGIB in our study.,Upper gastrointestinal bleeding is a common health problem in this part of rural SSA where schistosomiasis is endemic.,The clinical profile described is unique and is important for improved case management, and for future research.

Chronic schistosomiasis is associated with T cell hypo-responsiveness and immunoregulatory mechanisms, including induction of regulatory T cells (Tregs).,However, little is known about Treg functional capacity during human Schistosoma haematobium infection.,CD4+CD25hiFOXP3+ cells were characterized by flow cytometry and their function assessed by analysing total and Treg-depleted PBMC responses to schistosomal adult worm antigen (AWA), soluable egg antigen (SEA) and Bacillus Calmette-Guérin (BCG) in S. haematobium-infected Gabonese children before and 6 weeks after anthelmintic treatment.,Cytokines responses (IFN-γ, IL-5, IL-10, IL-13, IL-17 and TNF) were integrated using Principal Component Analysis (PCA).,Proliferation was measured by CFSE.,S. haematobium infection was associated with increased Treg frequencies, which decreased post-treatment.,Cytokine responses clustered into two principal components reflecting regulatory and Th2-polarized (PC1) and pro-inflammatory and Th1-polarized (PC2) cytokine responses; both components increased post-treatment.,Treg depletion resulted in increased PC1 and PC2 at both time-points.,Proliferation on the other hand, showed no significant difference from pre- to post-treatment.,Treg depletion resulted mostly in increased proliferative responses at the pre-treatment time-point only.,Schistosoma-associated CD4+CD25hiFOXP3+Tregs exert a suppressive effect on both proliferation and cytokine production.,Although Treg frequency decreases after praziquantel treatment, their suppressive capacity remains unaltered when considering cytokine production whereas their influence on proliferation weakens with treatment.

Dengue fever (DF) and malaria are the two major public health concerns in tropical countries such as Thailand.,Early differentiation between dengue and malaria could help clinicians to identify patients who should be closely monitored for signs of dengue hemorrhagic fever or severe malaria.,This study aims to build knowledge on diagnostic markers that are used to discriminate between the infections, which frequently occur in malaria-endemic areas, such as the ones in Thailand.,A retrospective study was conducted in Phop Phra Hospital, a hospital located in the Thailand-Burma border area, a malaria-endemic area, between 2013 and 2015.,In brief, data on 336 patients infected with malaria were compared to data on 347 patients infected with DF.,White blood cells, neutrophil, monocyte, eosinophil, neutrophil-lymphocyte ratio, and monocyte-lymphocyte ratio were significantly lower in patients with DF compared to patients with malaria (P < 0.0001).,In contrast, red blood cells, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were significantly higher in patients with DF as compared to patients with malaria (P < 0.0001).,A decision tree model revealed that using neutrophils, lymphocyte, MCHC, and gender was guided to discriminate between dengue and malaria infection.,This study concluded that several hematological parameters were different for diagnosing DF and malaria.,A decision tree model revealed that using neutrophils, lymphocyte, MCHC, and gender was guided to discriminate patients with dengue and malaria infection.,In addition, using these markers will thus lead to early detection, diagnosis, and prompt treatment of these tropical diseases.,The online version of this article (doi:10.1186/s40249-017-0238-x) contains supplementary material, which is available to authorized users.

Pneumonia is the major cause of mortality and morbidity in children worldwide.,Procalcitonin (PCT) and C-reactive protein (CRP) are used in developed countries to differentiate between viral and bacterial causes of pneumonia.,Validity of these markers needs to be further explored in Africa.,We assessed the utility of PCT and CRP to differentiate viral from invasive bacterial pneumonia in children <5 years hospitalized with clinical severe pneumonia (CSP) in rural Mozambique, a malaria-endemic area with high HIV prevalence.,Prognostic capacity of these markers was also evaluated.,Out of 835 children with CSP, 87 fulfilled definition of viral pneumonia and 89 of invasive bacterial pneumonia.,In absence of malaria parasites, levels of PCT and CRP were lower in the viral group when compared to the invasive bacterial one (PCT: median = 0.21 versus 8.31 ng/ml, p<0.001; CRP: 18.3 vs.,185.35 mg/l, p<0.001).,However, in presence of malaria parasites distribution between clinical groups overlapped (PCT: median = 23.1 vs.,21.75 ng/ml, p = 0.825; CRP: median = 96.8 vs.,217.4 mg/l, p = 0.052).,None of the two markers could predict mortality.,Presence of malaria parasites should be taken into consideration, either for clinical or epidemiological purposes, if using PCT or CRP to differentiate viral from invasive bacterial pneumonia in malaria-endemic areas.

Toxoplasma gondii is an intracellular protozoan that affects most species of endothermic animals including humans with a great infection rate.,The vertical transmission of T. gondii causes abortion, constituting a serious threat to humans and leading to great losses in livestock production.,Distinct from population structure of T. gondii in North America and Europe, Chinese 1 (ToxoDB #9) is a dominant genotype prevalent in China.,Among the isolates of Chinese 1, the Wh3 and Wh6 have different virulence and pathogenicity in mice.,However, little has been known about their difference at the genomic level.,Thus the next-generation sequencing (NGS) approach was used to discover the association of the phenotypical variations with the genome sequencing data and the expression and polymorphisms of the key effectors.,We successfully sequenced the genome of Chinese 1 strains of Wh3 and Wh6.,The average sequencing depths were 63.91 and 63.61 for Wh3 and Wh6, respectively.,The variations of both isolates were identified in comparison with reference genome of type I GT1 strain.,There were 505,645 and 505,856 SNPs, 30,658 and 30,004 indels, 4661 and 2320 SVs, and 1942 and 3080 CNVs for Wh3 and Wh6, respectively.,In target search variations of particular factors of T. gondii, the dense granule protein 3 (GRA3) and rhoptry neck protein 3 (RON3) were found to have 35 SNPs, 2 indels and 89 SNPs, 6 indels, respectively.,GRA3 and RON3 were both found to have higher expression levels in less virulent Wh6 than in virulent Wh3.,Both strains of type Chinese 1 share polymorphic GRA15II and ROPI/III with type I, II, and III strains.,Sequencing of the two strains revealed that genome structure of Chinese 1 and type I strains has considerable genomic variations.,Sequencing and qRT-PCR analyses of 26 effectors displayed a remarkable variation that may be associated with phenotype and pathogenic differences.,The online version of this article (doi:10.1186/s12864-015-2106-z) contains supplementary material, which is available to authorized users.

The increasing prevalence of Toxoplasma gondii infection in the human population in the Republic of Korea (= Korea) is due to various reasons such as an increase in meat consumption.,However, the importance of cats in transmitting T. gondii infection through oocysts to humans has seldom been assessed.,A total of 300 fecal samples of stray cats captured around Seoul from June to August 2013 were examined for T. gondii B1 gene (indicating the presence of oocysts) using nested-PCR.,Fourteen (4.7%) of 300 cats examined were positive for B1 gene.,Female cats (7.5%) showed a higher prevalence than male cats (1.4%).,Cats younger than 3 months (5.5%) showed a higher prevalence than cats (1.5%) older than 3 months.,For laboratory passage of the positive samples, the fecal suspension (0.2 ml) of B1 gene positive cats was orally inoculated into experimental mice.,Brain tissues of the mice were obtained after 40 days and examined for the presence of tissue cysts.,Two isolates were successfully passaged (designated KNIH-1 and KNIH-2) and were molecularly analyzed using the SAG5D and SAG5E gene sequences.,The SAG5D and SAG5E gene sequences showed high homologies with the ME49 strain (less virulent strain).,The results indicated the importance of stray cats in transmitting T. gondii to humans in Korea, as revealed by detection of B1 gene in fecal samples.,T. gondii isolates from cats were successfully passaged in the laboratory for the first time in Korea.

Recent studies have shown that a cytoplasmic virus called Leishmaniavirus (LRV) is present in some Leishmania species and acts as a potent innate immunogen, aggravating lesional inflammation and development in mice.,In humans, the presence of LRV in Leishmania guyanensis and in L. braziliensis was significantly correlated with poor treatment response and symptomatic relapse.,So far, no clinical effort has used LRV for prophylactic purposes.,In this context, we designed an original vaccine strategy that targeted LRV nested in Leishmania parasites to prevent virus-related complications.,To this end, C57BL/6 mice were immunized with a recombinant LRV1 Leishmania guyanensis viral capsid polypeptide formulated with a T helper 1-polarizing adjuvant.,LRV1-vaccinated mice had significant reduction in lesion size and parasite load when subsequently challenged with LRV1+ Leishmania guyanensis parasites.,The protection conferred by this immunization could be reproduced in naïve mice via T-cell transfer from vaccinated mice but not by serum transfer.,The induction of LRV1 specific T cells secreting IFN-γ was confirmed in vaccinated mice and provided strong evidence that LRV1-specific protection arose via a cell mediated immune response against the LRV1 capsid.,Our studies suggest that immunization with LRV1 capsid could be of a preventive benefit in mitigating the elevated pathology associated with LRV1 bearing Leishmania infections and possibly avoiding symptomatic relapses after an initial treatment.,This novel anti-endosymbiotic vaccine strategy could be exploited to control other infectious diseases, as similar viral infections are largely prevalent across pathogenic pathogens and could consequently open new vaccine opportunities.

Leishmania parasites cause a broad range of disease, with cutaneous afflictions being, by far, the most prevalent.,Variations in disease severity and symptomatic spectrum are mostly associated to parasite species.,One risk factor for the severity and emergence of leishmaniasis is immunosuppression, usually arising by coinfection of the patient with human immunodeficiency virus (HIV).,Interestingly, several species of Leishmania have been shown to bear an endogenous cytoplasmic dsRNA virus (LRV) of the Totiviridae family, and recently we correlated the presence of LRV1 within Leishmania parasites to an exacerbation murine leishmaniasis and with an elevated frequency of drug treatment failures in humans.,This raises the possibility of further exacerbation of leishmaniasis in the presence of both viruses, and here we report a case of cutaneous leishmaniasis caused by Leishmania braziliensis bearing LRV1 with aggressive pathogenesis in an HIV patient.,LRV1 was isolated and partially sequenced from skin and nasal lesions.,Genetic identity of both sequences reinforced the assumption that nasal parasites originate from primary skin lesions.,Surprisingly, combined antiretroviral therapy did not impact the devolution of Leishmania infection.,The Leishmania infection was successfully treated through administration of liposomal amphotericin B.

There is limited information on uptake of malaria testing among migrants who are a ‘high-risk’ population for malaria.,This was an explanatory mixed-methods study.,The quantitative component (a cross sectional analytical study-nation-wide migrant malaria survey in 2016) assessed the knowledge; health-seeking; and testing within 24 h of fever and its associated factors.,The qualitative component (descriptive design) explored the perspectives of migrants and health care providers [including village health volunteers (VHV)] into the barriers and suggested solutions to increase testing within 24 h.,Quantitative data analysis was weighted for the three-stage sampling design of the survey.,Qualitative data analysis involved manual descriptive thematic analysis.,A total of 3230 households were included in the survey.,The mean knowledge score (maximum score 11) for malaria was 5.2 (0.95 CI 5.1, 5.3).,The source of information about malaria was 80% from public health facility staff and 21% from VHV.,Among 11 193 household members, 964 (8.6%) had fever in last 3 months.,Health-seeking was appropriate for fever in 76% (0.95 CI 73, 79); however, only 7% (0.95 CI 5, 9) first visited a VHV while 19% (0.95 CI 16, 22) had self-medication.,Of 964, 220 (23%, 0.95 CI 20, 26) underwent malaria blood testing within 24 h.,Stable migrants, high knowledge score and appropriate health-seeking were associated with testing within 24 h.,Qualitative findings showed that low testing within 24 h despite appropriate health-seeking was due to lack of awareness among migrants regarding diagnosis services offered by VHV, delayed health-seeking at public health facilities and not all cases of fever being tested by VHV and health staff.,Providing appropriate behaviour change communication for migrants related to malaria, provider’s acceptance for malaria testing for all fever cases and mobile peer volunteer under supervision were suggested to overcome above barriers.,Providers were not testing all migrant patients with fever for malaria.,Low uptake within 24 h was also due to poor utilization of services offered by VHV.,The programme should seriously consider addressing these barriers and implementing the recommendations if Myanmar is to eliminate malaria by 2030.,The online version of this article (10.1186/s12936-018-2546-4) contains supplementary material, which is available to authorized users.

Currently less than 15% of children under five with fever receive recommended artemisinin-combination therapy (ACT), far short of the Roll Back Malaria target of 80%.,To understand why coverage remains low, it is necessary to examine the treatment pathway from a child getting fever to receiving appropriate treatment and to identify critical blockages.,This paper presents the application of such a diagnostic approach to the coverage of prompt and effective treatment of children with fever in rural Senegal.,A two-stage cluster sample household survey was conducted in August 2008 in Tambacounda, Senegal, to investigate treatment behaviour for children under five with fever in the previous two weeks.,The treatment pathway was divided in to five key steps; the proportion of all febrile children reaching each step was calculated.,Results were stratified by sector of provider (public, community, and retail).,Logistic regression was used to determine predictors of treatment seeking.,Overall 61.6% (188) of caretakers sought any advice or treatment and 40.3% (123) sought any treatment promptly within 48 hours.,Over 70% of children taken to any provider with fever did not receive an anti-malarial.,The proportion of febrile children receiving ACT within 48 hours was 6.2% (19) from any source; inclusion of correct dose and duration reduced this to 1.3%.,The proportion of febrile children receiving ACT within 48 hours (not including dose & duration) was 3.0% (9) from a public provider, 3.0% (9) from a community source and 0.3% (1) from the retail sector.,Inclusion of confirmed diagnosis within the public sector treatment pathway as per national policy increases the proportion of children receiving appropriate treatment with ACT in this sector from 9.4% (9/96) to an estimated 20.0% (9/45).,Process analysis of the treatment pathway for febrile children must be stratified by sector of treatment-seeking.,In Tambacounda, Senegal, interventions are needed to increase prompt care-seeking for fever, improve uptake of rapid diagnostic tests at the public and community levels and increase correct treatment of parasite-positive patients with ACT.,Limited impact will be achieved if interventions to improve prompt and effective treatment target only one step in the treatment pathway in any sector.

Malaria at international borders presents particular challenges with regards to elimination.,International borders share common malaria ecologies, yet neighboring countries are often at different stages of the control-to-elimination pathway.,Herein, we present a case study on malaria, and its control, at the border between Saudi Arabia and Yemen.,Malaria program activity reports, case data, and ancillary information have been assembled from national health information systems, archives, and other related sources.,Information was analyzed as a semi-quantitative time series, between 2000 and 2017, to provide a plausibility framework to understand the possible contributions of factors related to control activities, conflict, economic development, migration, and climate.,The malaria recession in the Yemeni border regions of Saudi Arabia is a likely consequence of multiple, coincidental factors, including scaled elimination activities, cross-border vector control, periods of low rainfall, and economic development.,The temporal alignment of many of these factors suggests that economic development may have changed the receptivity to the extent that it mitigated against surges in vulnerability posed by imported malaria from its endemic neighbor Yemen.,In many border areas of the world, malaria is likely to be sustained through a complex congruence of factors, including poverty, conflict, and migration.,The online version of this article (10.1186/s12916-018-1081-z) contains supplementary material, which is available to authorized users.

The draft Global Technical Strategy for malaria aims to eliminate malaria from at least 10 countries by 2020.,Yemen and Saudi Arabia remain the last two countries on the Arabian Peninsula yet to achieve elimination.,Over the last 50 years, systematic efforts to control malaria in the Kingdom of Saudi Arabia has successfully reduced malaria cases to a point where malaria is now constrained largely to Jazan Province, the most south-western area along the Red Sea.,The progress toward elimination in this province is reviewed between 2000 and 2014.,Data were obtained from the Ministry of Health case-reporting systems, activity reports, unpublished consultants reports, and relevant scientific published papers.,Sub-provincial population data were obtained the national household censuses undertaken in 2004 and 2010.,Rainfall data were obtained from the Meteorological Department in Jazan.,Between 2000 and 2014 there were 5522 locally acquired cases of malaria and 9936 cases of imported malaria.,A significant reduction in locally acquired malaria cases was observed from 2000 to 2014, resulting in an average annual incidence (2010-2014) of 0.3 cases per 10,000 population.,Conversely imported cases, since 2000, remain consistent and higher than locally acquired cases, averaging between 250 and 830 cases per year.,The incidence of locally acquired cases is heterogeneous across the Province, with only a few health districts contributing the majority of the cases.,The overall decline in malaria case incidence can be attributed to coincidental expansion of control efforts and periods of exceptionally low rainfall.,Jazan province is poised to achieve malaria elimination.,There is a need to change from a policy of passive case detection to reactively and proactively detecting infectious reservoirs that require new approaches to surveillance.,These should be combined with advanced epidemiological tools to improve the definitions of epidemiological receptive and hotspot malaria risk mapping.,The single largest threat currently remains the risks posed by imported infections from Yemen.

Planning and implementation of schistosomiasis control activities requires an understanding of the prevalence, intensity of infection and geographical distribution of the disease in different epidemiological settings.,Although, Tanzania is known to be highly endemic to schistosomiasis, there is paucity of data on the geographical distribution of schistosomiasis in potential large water bodies in the country.,Thus, the present study was conducted to determine the prevalence, infection intensities and geographical distribution of schistosomiasis along villages located on the shoreline of Lake Nyasa, southern Tanzania.,A cross-sectional study was conducted among 1560 children aged 1-13 years old living in villages located along the shoreline of Lake Nyasa.,A single urine and stool sample was obtained from each participating child and screened for S. mansoni using Kato Katz (KK) technique to detect eggs and using point-of-care circulating Cathodic Antigen (POC-CCA) test to detect antigen in urine.,Urine filtration technique was used to screen for S. haematobium eggs in urine samples.,Villages/primary school were mapped using geographical information system and prevalence map was generated using ArcView GIS software.,The overall prevalence of S. mansoni based on KK technique and POC-CCA test was 15.1% (95%CI: 13.4-16.9) and 21.8% (95%CI: 18.5-25.3) respectively.,The prevalence S. haematobium was 0.83% (95%CI: 0.5-1.4) and that of haematuria was 0.9%.,The arithmetic mean egg intensities for S. haematobium and S. mansoni were 18.5 mean eggs/10 ml (95%CI: 5.9-57.6) of urine and 34.7 mean epg (95%CI: 27.7-41.7) respectively.,Villages located on the southern end of the lake had significantly high prevalence of S. mansoni than those located on the northern part (χ2 = 178.7838, P = 0.001).,Cases of S. haematobium were detected only in three villages.,Both S. mansoni and S. haematobium infections occur in villages located along the shoreline of Lake Nyasa at varying prevalence.,These finding provide insights that can provide guidance in planning and implementation of MDA approach and other recommended measures such as improvement in sanitation, provision of clean water and behaviour changes through public health education.

Soil-transmitted helminths (STH) and Schistosoma mansoni infections are the major neglected tropical diseases that result in serious consequences on health, education and nutrition in children in developing countries.,The Ethiopian Orthodox church students, who are called Yekolotemari in Amharic, live in areas with poor sanitation and hygiene.,Moreover, they are not included in the national STH control programs.,Thus, STH and S. mansoni infections prevalence is unknown.,A cross-sectional study was conducted on 384 students in June 2014 to determine STH and S. mansoni infections prevalence.,Moreover, the knowledge of students about STH and S. mansoni was assessed.,Data on knowledge and clinical symptoms were collected using structured questionnaires via face to face interview.,Stool specimens were examined by formol-ether concentration method.,The overall prevalence of intestinal helminths infections was 85.9% (95% confidence interval (CI): 82.1-89%).,STHs infections prevalence was 65.6% (95% CI: 60.7-70.2%).,The prevalence of hookworm, Ascaris lumbricoides and Trichuris trichiura were 31.8% (95% CI: 27.3-36.6%), 29.4% (25-31%) and 3.1% (1.8-5.4%), respectively.,On the other hand, S. mansoni prevalence was 14.3% (95% CI: 11.1-18.1%).,Majority of students infected with S. mansoni had bloody stool with crud odds-ratio of 2.9 (95% CI: 1.5-5.5).,Knowledge assessment showed that 50 (13%) and 18 (4.9%) of the respondents knew about transmission of STH and S. mansoni, respectively.,The prevalence of STH and S. mansoni infections were high thus de-worming program should include the students of Ethiopian Orthodox churches.,Furthermore, provision and use of sanitary facilities, health education for students to create awareness of parasitic infections and improved personal hygiene should be in place.

Malaria transmission is known to be strongly impacted by temperature.,The current understanding of how temperature affects mosquito and parasite life history traits derives from a limited number of empirical studies.,These studies, some dating back to the early part of last century, are often poorly controlled, have limited replication, explore a narrow range of temperatures, and use a mixture of parasite and mosquito species.,Here, we use a single pairing of the Asian mosquito vector, An. stephensi and the human malaria parasite, P. falciparum to conduct a comprehensive evaluation of the thermal performance curves of a range of mosquito and parasite traits relevant to transmission.,We show that biting rate, adult mortality rate, parasite development rate, and vector competence are temperature sensitive.,Importantly, we find qualitative and quantitative differences to the assumed temperature-dependent relationships.,To explore the overall implications of temperature for transmission, we first use a standard model of relative vectorial capacity.,This approach suggests a temperature optimum for transmission of 29°C, with minimum and maximum temperatures of 12°C and 38°C, respectively.,However, the robustness of the vectorial capacity approach is challenged by the fact that the empirical data violate several of the model’s simplifying assumptions.,Accordingly, we present an alternative model of relative force of infection that better captures the observed biology of the vector-parasite interaction.,This model suggests a temperature optimum for transmission of 26°C, with a minimum and maximum of 17°C and 35°C, respectively.,The differences between the models lead to potentially divergent predictions for the potential impacts of current and future climate change on malaria transmission.,The study provides a framework for more detailed, system-specific studies that are essential to develop an improved understanding on the effects of temperature on malaria transmission.

Over a century since Ronald Ross discovered that malaria is caused by the bite of an infectious mosquito it is still unclear how the number of parasites injected influences disease transmission.,Currently it is assumed that all mosquitoes with salivary gland sporozoites are equally infectious irrespective of the number of parasites they harbour, though this has never been rigorously tested.,Here we analyse >1000 experimental infections of humans and mice and demonstrate a dose-dependency for probability of infection and the length of the host pre-patent period.,Mosquitoes with a higher numbers of sporozoites in their salivary glands following blood-feeding are more likely to have caused infection (and have done so quicker) than mosquitoes with fewer parasites.,A similar dose response for the probability of infection was seen for humans given a pre-erythrocytic vaccine candidate targeting circumsporozoite protein (CSP), and in mice with and without transfusion of anti-CSP antibodies.,These interventions prevented infection more efficiently from bites made by mosquitoes with fewer parasites.,The importance of parasite number has widespread implications across malariology, ranging from our basic understanding of the parasite, how vaccines are evaluated and the way in which transmission should be measured in the field.,It also provides direct evidence for why the only registered malaria vaccine RTS,S was partially effective in recent clinical trials.

Despite that over 90 million pregnancies are at risk of Plasmodium vivax infection annually, little is known about the epidemiology and impact of the infection in pregnancy.,We undertook a health facility-based prospective observational study in pregnant women from Guatemala (GT), Colombia (CO), Brazil (BR), India (IN) and Papua New Guinea PNG).,Malaria and anemia were determined during pregnancy and fetal outcomes assessed at delivery.,A total of 9388 women were enrolled at antennal care (ANC), of whom 53% (4957) were followed until delivery.,Prevalence of P. vivax monoinfection in maternal blood at delivery was 0.4% (20/4461) by microscopy [GT 0.1%, CO 0.5%, BR 0.1%, IN 0.2%, PNG 1.2%] and 7% (104/1488) by PCR.,P. falciparum monoinfection was found in 0.5% (22/4463) of women by microscopy [GT 0%, CO 0.5%, BR 0%, IN 0%, PNG 2%].,P. vivax infection was observed in 0.4% (14/3725) of placentas examined by microscopy and in 3.7% (19/508) by PCR.,P. vivax in newborn blood was detected in 0.02% (1/4302) of samples examined by microscopy [in cord blood; 0.05% (2/4040) by microscopy, and 2.6% (13/497) by PCR].,Clinical P. vivax infection was associated with increased risk of maternal anemia (Odds Ratio-OR, 5.48, [95% CI 1.83-16.41]; p = 0.009), while submicroscopic vivax infection was not associated with increased risk of moderate-severe anemia (Hb<8g/dL) (OR, 1.16, [95% CI 0.52-2.59]; p = 0.717), or low birth weight (<2500g) (OR, 0.52, [95% CI, 0.23-1.16]; p = 0.110).,In this multicenter study, the prevalence of P. vivax infection in pregnancy by microscopy was overall low across all endemic study sites; however, molecular methods revealed a significant number of submicroscopic infections.,Clinical vivax infection in pregnancy was associated with maternal anemia, which may be deleterious for infant’s health.,These results may help to guide maternal health programs in settings where vivax malaria is endemic; they also highlight the need of addressing a vulnerable population such as pregnant women while embracing malaria elimination in endemic countries.

Most malarious countries outside of Africa are co-endemic for Plasmodium falciparum and Plasmodium vivax.,The comparative burden of anaemia in the community caused by these two species is incompletely characterized.,A three-stage, cross-sectional, community survey was used to determine the proportion of moderate or severe anaemia (haemoglobin <7 g/dL) attributable to patent P. vivax, P. falciparum and mixed parasitaemia in Papua, Indonesia.,Adjusted population-attributable fractions were calculated from multivariable logistic regression models.,Eight hundred and twenty-five households were surveyed with a total of 5255 occupants, 3890 (74 %) of whom were present and provided a blood sample.,Plasmodium falciparum parasitaemia was present in 8.1 % (n = 315) of participants, P. vivax in 6.4 % (n = 250) and mixed infections in 1.9 % (n = 72).,Overall, P. falciparum was associated with a mean reduction in haemoglobin of 1.16 g/dL compared to those without patent parasitaemia [95 % confidence interval (95 % CI) 0.91, 1.41 g/dL].,The corresponding values for P. vivax and mixed infections were 0.66 g/dL (95 % CI 0.35, 0.96) and 1.25 g/dL (0.71, 1.80), respectively.,Overall, 16.7 % (95 % CI 8.52, 24.2 %) of haemoglobin concentrations <7 g/dL in the community were estimated to be attributable to patent parasitaemia.,The fractions for infants and 1-5 years old were 34.4 % (95 % CI −3.30, 58.3 %) and 23.2 % (95 % CI 3.34, 39.0 %), respectively.,Plasmodium vivax was associated with a greater than threefold higher attributable fraction of anaemia in infants compared with P. falciparum [27.6 % (95 % CI −3.20, 49.2 %) versus 7.94 % (−5.87, 20.0 %)].,Despite comparatively low-level endemicity, malaria is associated with a significant proportion of all cases of community anaemia in southern Papua.,Contrary to its benign reputation, P. vivax is an important and preventable risk factor for anaemia during infancy-a probable consequence of relapsing disease prior to the development of immunity.

Malaria control in Africa relies extensively on indoor residual spraying (IRS) and insecticide-treated nets (ITNs).,IRS typically targets mosquitoes resting on walls, and in few cases, roofs and ceilings, using contact insecticides.,Unfortunately, little attention is paid to where malaria vectors actually rest indoors, and how such knowledge could be used to improve IRS.,This study investigated preferred resting surfaces of two major malaria vectors, Anopheles funestus and Anopheles arabiensis, inside four common house types in rural south-eastern Tanzania.,The assessment was done inside 80 houses including: 20 with thatched roofs and mud walls, 20 with thatched roofs and un-plastered brick walls, 20 with metal roofs and un-plastered brick walls, and 20 with metal roofs and plastered brick walls, across four villages.,In each house, resting mosquitoes were sampled in mornings (6 a.m.-8 a.m.), evenings (6 p.m.-8 p.m.) and at night (11 p.m.-12.00 a.m.) using Prokopack aspirators from multiple surfaces (walls, undersides of roofs, floors, furniture, utensils, clothing, curtains and bed nets).,Overall, only 26% of An. funestus and 18% of An. arabiensis were found on walls.,In grass-thatched houses, 33-55% of An. funestus and 43-50% of An. arabiensis rested under roofs, while in metal-roofed houses, only 16-20% of An. funestus and 8-30% of An. arabiensis rested under roofs.,Considering all data together, approximately 40% of mosquitoes rested on surfaces not typically targeted by IRS, i.e. floors, furniture, utensils, clothing and bed nets.,These proportions were particularly high in metal-roofed houses (47-53% of An. funestus; 60-66% of An. arabiensis).,While IRS typically uses contact insecticides to target adult mosquitoes on walls, and occasionally roofs and ceilings, significant proportions of vectors rest on surfaces not usually sprayed.,This gap exceeds one-third of malaria mosquitoes in grass-thatched houses, and can reach two-thirds in metal-roofed houses.,Where field operations exclude roofs during IRS, the gaps can be much greater.,In conclusion, there is need for locally-obtained data on mosquito resting behaviours and how these influence the overall impact and costs of IRS.,This study also emphasizes the need for alternative approaches, e.g. house screening, which broadly tackle mosquitoes beyond areas reachable by IRS and ITNs.

Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) represent the front-line tools for malaria vector control globally, but are optimally effective where the majority of baseline transmission occurs indoors.,In the surveyed area of rural southern Tanzania, bed net use steadily increased over the last decade, reducing malaria transmission intensity by 94%.,Starting before bed nets were introduced (1997), and then after two milestones of net use had been reached-75% community-wide use of untreated nets (2004) and then 47% use of ITNs (2009)-hourly biting rates of malaria vectors from the Anopheles gambiae complex and Anopheles funestus group were surveyed.,In 1997, An. gambiae s.l. and An. funestus mosquitoes exhibited a tendency to bite humans inside houses late at night.,For An. gambiae s.l., by 2009, nocturnal activity was less (p = 0.0018).,At this time, the sibling species composition of the complex had shifted from predominantly An. gambiae s.s. to predominantly An. arabiensis.,For An. funestus, by 2009, nocturnal activity was less (p = 0.0054) as well as the proportion biting indoors (p < 0.0001).,At this time, An. funestus s.s. remained the predominant species within this group.,As a consequence of these altered feeding patterns, the proportion (mean ± standard error) of human contact with mosquitoes (bites per person per night) occurring indoors dropped from 0.99 ± 0.002 in 1997 to 0.82 ± 0.008 in 2009 for the An. gambiae complex (p = 0.0143) and from 1.00 ± <0.001 to only 0.50 ± 0.048 for the An. funestus complex (p = 0.0004) over the same time period.,High usage of ITNs can dramatically alter African vector populations so that intense, predominantly indoor transmission is replaced by greatly lowered residual transmission, a greater proportion of which occurs outdoors.,Regardless of the underlying mechanism, the residual, self-sustaining transmission will respond poorly to further insecticidal measures within houses.,Additional vector control tools which target outdoor biting mosquitoes at the adult or immature stages are required to complement ITNs and IRS.