Plasmodium family of parasites, especially P.falciparum and P. vivax, is a major health problem in many countries in the tropical and subtropical regions of the world. The disease presents a wide array of systemic clinical conditions and several life-threatening organ pathologies, including the dreaded cerebral malaria. Like many other infectious diseases, malaria is an inflammatory response-driven disease, and positive outcomes to infection depend on finely tuned regulation of immune responses that efficiently clear parasites and allow protective immunity to develop. Immune responses initiated by the innate immune system in response to parasites play key roles both in protective immunity development and pathogenesis. Initial pro-inflammatory responses are essential for clearing infection by promoting appropriate cell-mediated and humoral immunity. However, elevated and prolonged pro-inflammatory responses owing to inappropriate cellular programming contribute to disease conditions. A comprehensive knowledge of the molecular and cellular mechanisms that initiate immune responses and how these responses contribute to protective immunity development or pathogenesis is important for developing effective therapeutics and/or a vaccine. Historically, in efforts to develop a vaccine, immunity to malaria was extensively studied in the context of identifying protective humoral responses, targeting proteins involved in parasite invasion or clearance. The innate immune response was thought to be non-specific. However, during the past two decades, there has been a significant progress in understanding the molecular and cellular mechanisms of host-parasite interactions and the associated signaling in immune responses to malaria. Malaria infection occurs at two stages, initially in the liver through the bite of a mosquito, carrying sporozoites, and subsequently, in the blood through the invasion of red blood cells by merozoites released from the infected hepatocytes. Soon after infection, both the liver and blood stage parasites are sensed by various receptors of the host innate immune system resulting in the activation of signaling pathways and production of cytokines and chemokines. These immune responses play crucial roles in clearing parasites and regulating adaptive immunity. Here, we summarize the knowledge on molecular mechanisms that underlie the innate immune responses to malaria infection.Malaria caused by the  Plasmodium. Five parasite species infect humans that include Plasmodium falciparum, P. vivax, P. malariae, P. ovale, and P. knowlesi  bind to certain cell surface proteins of vascular endothelia, including CD36, intracellular adhesion molecule 1 (ICAM-1), vascular adhesion molecule 1 (VCAM-1), and endothelial protein receptor (EPCR) . PfEMP1 confers virulence to P. falciparum through IRBC binding to endothelial cells in various organs contributing to microvascular plugging and hypoxia. In addition, IRBC-binding and parasite accumulation amplify inflammatory responses locally, leading to immune cell infiltration, endothelial damage, and organ dysfunction and failure. P. vivax lacks PfEMP1 ortholog  , 13–20.  surface –23. This surface . The binar genes , 16, 25.ortholog  and thus numbers , 27–30.  factors , 32.Innate immune responses that are initiated in response to malaria infection play key roles both in the development of protective immunity and pathogenesis , 33–38. During the past two decades, there has been a substantial progress in our understanding of the host receptors that sense parasite factors involved in inducing immune responses and the associated signaling pathways –47. A suPlasmodium species  of pathogens called pathogen-associated molecular patterns (PAMPs); these include bacterial LPS and peptidoglycan, fungal glucans, and microbial DNA and RNA, and even self-DNA under certain pathologic conditions –61. HostA notable feature of malaria infection is that the liver stage is clinically completely silent, that is, the host does not exhibit any symptoms of malaria –73. All P. berghei- and P. yoelii-infected mice show that, although parasites inside hepatocytes are shielded from recognition by Mφs and dendritic cells (DCs), the growing parasites are recognized by the cytosolic PRRs of hepatocytes, initiating antiparasitic type I IFN response  is the first factor that was identified as a malaria parasite PAMP  induces cytokine and chemokine responses by human plasmacytoid DCs (pDCs) and mouse DCs through the activation of TLR9-MyD88 signaling pathway. Subsequently, it was shown that the TLR9 signaling-inducing malaria factor is DNA  DNA, and self-DNA in some pathological situations, function as PAMP and are recognized by TLR9 in endosomes and by DNA sensors in the cytosol –60. In tr is DNA , 124. TLr is DNA , 69. TheG motifs . The higlciparum .P. falciparum genomic DNA contains >80% AT nucleotides. The AT-rich motifs of parasite DNA form loop structures, which have been shown to induce type I IFN response through STING-TBK1-IRF3 signaling  during the blood stage malaria infection , 8079, 8nfection . Parasitnfection , 128. Tynfection . RNA of nfection .P. falciparum has been reported to induce cytokine responses through TLR7 recognition, the reported activity appears to be very low  phagocytic uptake of parasites, and (iii) enhancing innate immune responses , which is also known as activated protein C (APC) receptor, is a transmembrane glycoprotein in vasculatures that binds protein C and promotes thrombin-thrombomodulin complex-mediated protein C activation . Under nP. falciparum in the brain through the binding of PfEMP1 on the surface of IRBCs to endothelial cells (P. berghei ANKA-infected mice and that ICAM-1 deficient mice survive >15 days compared to 6–8 days in wild type (WT) mice  mice . HoweverWT) mice . NK cellWT) mice . Similarignaling , 122  cytokines produced through the activation of TLR7-MyD88 and IRF7 signaling . Early tted mice , 127. Twnfection , 128. Thnfection . It has nfection . Additioignaling , 108. Itignaling , exposinnfection . Collectignaling , 128, whhei ANKA . The proignaling , 110. Th days pi .P. yoelii YM infection resulted in increased IFN-γ levels, significantly decreased parasitemia and resistant to parasite burden-dependent death , deficiency in IFNαR or treatment with anti-IFNαR1 antibody resulted in increased IFN-γ production, increased number of IFN-γ-positive NK and CD4+ T cells in the spleen, and significantly decreased parasitemia and protection from cerebral malaria (P. yoelii YM infection promoted antiparasitic immunity. In this case, blocking of SOCS1, a suppressor of cytokine signaling 1, expression resulted in high levels of type I IFN production, leading to increased IFN-γ production and reduced parasitemia, protecting mice from parasite burden-dependent death (P. berghei ANKA-infected mice with recombinant IFN-α, which to a certain extent resembles a situation of high levels of type I IFN production at early stage of infection, also significantly increased IFN-γ production by splenic CD8+ T cells, markedly reducing parasitemia and preventing cerebral malaria (P. berghei ANKA-infected mice with recombinant IFN-β resulted in reduced TNF-α and IFN-γ production, decreased expression of ICAM-1 and CXCL9 in the brain, reduced CXCR3 expression by T cells and T cell infiltration to the brain, thereby significantly preventing cerebral malaria and increasing mice survival (Early type I IFN response to malaria infection contributes to the suppression of antiparasitic immunity and promotes cerebral and other severe malaria illnesses under certain situations. This is evident from the observations that deficiency in IFNαR in nt death . Also, i malaria , 176. Frnt death . Consistnt death , daily t malaria . The ressurvival . Thus, tP. berghei ANKA-infected mice, Palomo et al. observed contrasting immune responses (P. berghei ANKA-infected mice deficient in IFNαR had similar parasitemia, reduced expression of IFN-γ and granzyme B by T cells, decreased expression of T cell-attracting chemokine CXCL9, and low infiltration of CXCR3+-expressing CD8 T cells to the brain. A notable difference in these studies is that the latter study used GFP knock-in transgenic parasite clone, which appeared to have slower growth rate than the WT parasites used in the former study. These differences may alter the dynamics of immune responses. Nevertheless, the results agree with the notion that type I IFNs play distinct roles under different malaria conditions.Compared to the results of two studies outlined above , 176, whesponses , althougOverall, the available data indicate that type I IFNs play disparate roles in malaria infection depending on the timing and amount of production, relative levels of IFN-α, IFN-β and perhaps other isomers, and compositions of cellular and cytokine milieu during the progression of infection, and parasite strains. A recent review provides a comprehensive and up-to-date account on the role and contrasting effects of type I IFNs in malaria . Type I In addition to producing type I IFNs, DCs produce a wide range of pro-inflammatory cytokines, including TNF-α, IL-12, and IL-6, and chemokines, such as CXCL1, CXCL2, CCL2, CCL5, CXCL9, and CXCL10 in response to malaria parasites, and play crucial roles in malaria immunity and pathogenesis , 184–186P. falciparum RNA appears to have very low immunostimulatory activity, it is possible that TLR7 has either minor or no role in human malaria. Accumulated evidence indicates that TLRs prominently contribute malaria immunity and pathology, whereas other signaling mechanisms such as inflammasome and adherence-mediated signaling may play minor roles (DNA and RNA play prominent roles in mouse malaria immunity and pathogenesis; under certain conditions TLR2 and TLR4 also play important roles. As such, studies in various mouse models have demonstrated that TLR9, TLR7, TLR4, and TLR2 play important roles in malaria immunity and cerebral, placental and other severe malaria pathology , 195–201or roles , 215.P. yoelii 17XNL strain and P. chabaudi that exhibit slow growth rates during the initial phase of infection, pro-inflammatory responses are protective by facilitating anti-parasitic effector function and cell-mediated immunity. In contrast, in the case of cytoadherent parasites, such as P. berghei ANKA that sequesters in brain, lungs, liver and adipose tissues, and P. berghei NK65 that sequesters in lungs and liver, pro-inflammatory responses are pathogenic by promoting cytotoxicity in effector cells, which cause organ damage. In this regard, the observations made in mouse models parallel those of vivax and falciparum malaria in humans. In P. falciparum infection, strong pro-inflammatory responses contribute to an effective control of parasitemia which otherwise results in fulminant infection (P. vivax, which is relatively slow growing and does not cytoadhere except at low levels in lungs and the placenta (P. falciparum.The contribution of pro-inflammatory responses produced by the innate immune system to protective immunity and pathogenesis is primarily context dependent. In non-cytoadherent parasites, such as nfection , 42. Howplacenta , despiteMalaria continues to be a major global health problem. In many endemic areas, parasites are becoming increasingly resistant to the currently widely used artemisinin-based combination drugs, which have been very effective in treating infection. Therefore, new drugs or other treatment strategies are urgently needed. Mass vaccination is the best strategy to prevent malaria. However, despite huge efforts during the past decades in many laboratories around the world, obtaining an efficacious vaccine suitable for mass vaccination remains challenging. It is thought that better understanding of molecular and cellular processes involved in the development of protective immunity and those that contribute to severe pathogenesis will be useful in designing an effective vaccine. During the past decades, a significant progress has been made in identifying the parasite factors and host receptors involved in the activation of the innate immune system and the associated cell signaling pathways. Significant progress has also been made in understanding how cellular activation and immune responses initiated upon parasite-host interactions influence subsequent development of antiparasitic immunity and contribute to severe pathogenesis.All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Accurate identification of malaria cases is crucial to the management of cases and the eventual success of malaria eradication agenda. This study is designed to evaluate the discriminatory and predictive accuracy of malaria rapid diagnostic tests (RDTs) in Nigeria.The data obtained during the 2015 Nigeria Malaria Indicator Survey was used to quantify the discriminatory accuracy of the RDT against the microscopy through the analysis of its sensitivity, specificity, positive (LR+) and negative (LR−) likelihood ratio. The positive (PPV) and negative (NPV) predictive values, area under the receiver operating characteristic curve, and diagnostic odds ratio were used to assess the predictive accuracy of the RDTs using expert microscopy as a gold standard at p = 0.05. The McNemar paired test and the Kappa statistics were used to assess the level of agreement between the diagnostic tests.There was a significant but not an excellent agreement between the results of the RDT and microscopy tests (p < 0.001). The overall sensitivity of the RDT was 87.6% (85.9–89.2%), specificity was 75.8% (74.4–77.1%), while the diagnostic accuracy stood at 79.0% (77.9–80.0%). The LR+, LR−, PPV and NPV were 3.6 (3.4–3.8) and 0.16 (0.14–0.19), 57.5% (56.1–58.9%) and 94.2% (93.5–94.9%), respectively. The sensitivity of RDT increased as the age of the children increased, from 85.7% among those aged 0–6 months to 86.1% in 7–23 month olds to 88.1% among those aged 24–59 months, but the reverse was the specificity. For children with severe anaemia, the sensitivity of the RDT was nearly 100% compared with a specificity of 39%. While the sensitivity and the PPV reduced with children’s level of anaemia, the higher the severity of anaemia, the lower the NPV, specificity, the diagnostic accuracy of the RDT. The odds of RDT being sensitive was about 50% [adjusted Odds Ratio (aOR) = 0.52 (95% CI 0.30–0.90)] lower among children aged 7–23 months compared with those aged 24–59 months while the odds of RDT being sensitive was 2 times [aOR = 2.15 (95% CI 1.67–2.77)] higher among those 7–23 months than among those aged 24–59 months.Although there was a significant agreement in the outcomes of RDT and microscopy tests, the discriminatory accuracy of RDT was weak. Also, the predictive accuracy, especially the PPV of the RDTS, were very low. These measures of accuracies differed across the age of the children, level of anaemia, recent experience of malaria and other characteristics. Without an accurate, efficient and reliable diagnosis of malaria, the goal of eliminating malaria and reduction of malaria-related deaths to zero by 2020 will only remain elusive.The online version of this article (10.1186/s12936-019-2678-1) contains supplementary material, which is available to authorized users. Malaria remains a major public health challenge in sub-Sahara Africa, especially Nigeria –3. DespiMalaria diagnosis is a key pillar in the eradication of malaria in Africa. The World Health Organization (WHO) recommends that malaria case management is based on parasite diagnosis in all cases , 6 and tAlthough the use of RDT has increased tremendously over the past few years and account for more than two-thirds of malaria diagnoses in Africa , the outLiterature has documented the specificities, sensitivities, numbers of false positives and false negatives and variabilities in temperature tolerances of these tests as some of the difficulties and challenges facing current RDTs . ConclusThe consequences of erroneous and wrong diagnosis are enormous. These errors could be either false negative or false positive errors. The false negative errors occur when the disease is missed when indeed, it is present. They often result in people foregoing needed treatment and could lead to the chronic stage of disease or even death. The false positive errors are due to wrongful confirmation that a disease is present. It leads to a wrong focus on disease-free subjects which may result in unnecessary treatment and sometimes overtreatment. It could lead to a negative impact, personal inconvenience, unwarranted stress, anxiety. Eusebi et al. have already advocated for strict evaluation of the diagnostic accuracy of testing procedure aimed at validating any potential diagnostic tool .This study is, therefore, designed to provide the malaria programmers with situation assessment of the accuracy of RDTs being used in Nigeria and to also determine the distribution of the levels of accuracy in terms of discrimination and prediction. It was hypothesized in this study that the outcomes of both the RDT and microscopy malaria tests are not in agreement. The findings in this study will improve programme implementation and enhance the much-needed progress towards malaria control and eradication in Nigeria.Plasmodium falciparum is the primary cause of malaria in Nigeria [The data used for this study were collected between October and November 2015 during the 2015 NMIS that was jointly implemented by the National Malaria Elimination Programme (NMEP), the National Population Commission (NPopC), the National Bureau of Statistics (NBS), and the Malaria Partnership in Nigeria. Nigeria is a tropical country (2.66°E–14.68°E longitudes and 4.28°N–13.89°N latitudes) located at the Gulf of Guinea on the west coast Africa occupying almost a million square metres. Nigeria climates range from arid to humid equatorial. There are wide climatic variations in different parts of Nigeria. Towards the coast, temperature ranges 26–32 °C with high humidity but a much hotter temperature is prevalent in the North. Nigeria experiences a wet season from April to October with lower monthly temperatures and a dry season from November to March, with average midday temperatures of about 38 °C. Rainfall varies in Nigeria with 70 inches in the western coasts, 170 inches in the eastern coasts and 20 inches in the extreme north [The sample design was cross-sectional and nationally representative. The most current 2006 Nigeria National Population and Housing Census were used as the sampling frame. The states were subdivided into local government areas (LGAs), with subsequent sub-divisions into localities and convenient areas, also called census enumeration areas (EAs). The EAs, which are referred to as clusters, are used as the primary sampling unit in the 2015 NMIS. There were 138 clusters in urban areas and 195 in rural areas totalling 333 clusters. A two-stage sampling strategy was used for the survey. At the first stage, 9 representative clusters were randomly selected from each of the 36 states and the FCT. In the second stage, 25 households each were randomly selected in each cluster. Thereafter, all women aged 15–49 residents in the selected households were interviewed together. Also, all children aged 6–59 months in the selected households were tested for malaria and anaemia.® analyser. The results were given to each child’s parent or guardian in both verbal and written forms within a minute of testing. Referrals for follow-up care were offered according to guidelines. The anaemia test results were recorded on the Biomarker Questionnaire, and the households counselled appropriately.Anaemia was included in the 2015 NMIS for children aged 6–59 months as a result of the documented strong relationship between malaria infection and anaemia. With the use of a single-use retractable, spring-loaded, sterile lancet, finger/heel-prick, blood samples were drawn from every participating children and put in a microcuvette. Also, the Haemoglobin analysis was carried out on site using a battery-operated portable HemoCuePlasmodium falciparum in human whole blood” [Using the same blood sample collected for anaemia testing, a drop of blood was tested immediately with the SD BIOLINE Malaria Ag P.f (HRP-II)™  RDT, being a qualitative test “to detect histidine-rich protein II antigen of e blood” . The tese blood” .In addition to the RDT, thick and thin blood smears were prepared in the field. Each blood smear slide was labelled according to guidelines and transmitted to the laboratory. The thick and thin smear slides were stained at zonal staining and taken to the ANDI Centre of Excellence for Malaria Diagnosis, University of Lagos, Nigeria for logging and microscopic reading. Other details of the testing procedures have been reported earlier .The outcome variable in this study is the result of the RDT and microscopy malaria tests while the independent factors considered are child’s household wealth quintiles, child age, and sex of children, mother’s educational attainment, place of residence, region, sleeping under a long-lasting insecticide-treated net or any ever treated nets recently, experience of fever within 2 weeks preceding the survey, and the level of anaemia as used in earlier studies , 16. TheThere were a total of 7011 children aged 6–59 months across all the households visited during the survey. Basic descriptive statistics were used to describe the under-five children with respect to the characteristics of their mothers. The McNemar paired test and the Kappa statistics were used to test the hypothesis of non-agreement and to determine the level of agreement between the outcomes of the diagnostic tests respectively. Diagnostic test parameters including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) was used to determine the accuracy of the malaria RDT results in comparison with the “Gold standard” results from microscopy tests. The choice of microscopy as the gold standard is because it is the best available method for establishing the presence or absence of malaria. Also, the microscopy test results have been used as the gold standards in similar previous studies , 13, 16.The discriminatory accuracy of a diagnostic test is measured by its ability to correctly classify known cases  and non-cases subjects  . The senX denote the true state of a person (microscopy test results) with microscopy positive = D+ and negative = D−. Also, let Y be the outcome of the RDT test, with RDT positive = T+ and negative = T−. Then,Let The positive likelihood ratio (LR+) and the negative likelihood ratio (LR−) are calculated asl et al. . The unil et al. .However, there is a need to determine the predictive values since sensitivities and specificities are not measures of prediction . PredictThe accuracy of a test = (TP + TN)/(TP + TN + FP + FN) and its confidence intervals are the standard logits as given by Mercaldo et al. . The preThe ROC analysis is used in diagnostic screening evaluation to quantify the accuracy of diagnostic tests . The “roAmong the 7011 children included in the survey, only 6025 and 5753 children were tested for malaria parasite using the microscopy and the RDT methods respectively. The distribution of the results of the tests by selected children characteristics is presented in Table P. falciparum was the main (94%) type of malaria parasite found through the blood film microscopy among the U5 children, followed by the Plasmodium ovale and Plasmodium malariae at 5% and 1%, respectively.In addition, the level of anaemia was significantly associated with the presence of malaria parasite as evidenced by both the RDT and microscopic tests. Children with severe anaemia had higher malaria prevalence  compared with others that were not anaemic . Although not stated in the tables, The outcome of the McNemar paired test used in testing the hypothesis of non-agreement between the RDT and microscopy tests showed evidence of a significant agreement between the two tests with test statistics of 553.47 with p < 0.0001 while the Kappa statistics of the agreement was 0.55.Based on the microscopy test as a gold standard, Table Also, there was a significant PPV gap of 14% in a rural area (60%) compared with the urban area (46%) (p < 0.05) but with a closer NPV 92% vs 98%) (p < 0.05). The overall accuracy, the sensitivity, the specificity, LR+, and NPV of the RDT were generally and significantly higher across the southern regions in Nigeria than in the northern regions (p < 0.05). For children with severe anaemia, the sensitivity of the RDT was nearly 100% compared with a specificity of 39% (p < 0.05). It appeared that the discriminatory accuracy reduced with children level of anaemia but the higher the severity of the anaemia, the lower its specificity (p < 0.05). However, both the LR+ and the LR− increased as the severity of anaemia increased (p < 0.05). For the predictive accuracy, PPV reduced with reduced severity from 77 to 44% (p < 0.05) among children that didn’t have anaemia while the NPV increased significantly from 90% among children that had severe anaemia to 97% among those that didn’t have anaemia (p < 0.05) as shown in Table % vs 98% Among all the under-five children, the prior probability of malaria was 27%. For the positive tests  lower among children aged 7–23 months compared with those aged 24–59 months. The adjusted odds of RDT being sensitive was 11 times  and 2 times  higher among those aged 0–6 months and 7–23 months respectively than among those aged 24–59 months. Also, the adjusted odds of RDT being sensitive was significantly over five times more likely among children with severe anaemia than those with moderate anaemia, while the odds of being specific was about three times higher among children with no anaemia than children with moderate anaemia (p < 0.05)  than being specific (76%). The sensitivity in the current study is comparable to the sensitivity of 89% but lower than the specificity of 88% reported in an earlier longitudinal study in Tanzania . In the Murungi et al. noted that poor specificity in a diagnostic test may negatively impact RDT-based diagnostic strategies for malaria . The widOn the predictive accuracy of the RDTs used in malaria diagnosis in the current study, the PPV was low at 58% while the NPV was relatively high at 94%, respectively. This finding suggests that the likelihood of having malaria when the RDT test is positive is only about half while the likelihood of being disease-free when the RDT test is negative is very high. In contrast, Hopkins et al. found that the PPV of the HRP2-based test was 98% compared with “the expert” microscopy, with an NPV of 97% for the HRP2-based test [In the current study, the sensitivity of RDT increased as the age of the children increased, while the specificity reduced. This is similar to the findings of Nankabinwa et al. that the sensitivity and specificity of PCR and RDTs varied by age of the study participants. While the sensitivity of the RDT was similar for both males and females, the specificity was only slightly higher among females than males . All theAlso, the level of anaemia influenced both the discriminatory and the predictive accuracies of the RDTs. The RDTs were totally sensitive and less than 40% specific among children with severe anaemia. The higher the severity of anaemia in children, the higher the sensitivity and the lower the specificity. In a similar trend, PPV reduced with reducing anaemia severity, while the NPV increased with a reduction in the level of severity of anaemia.Although, all the tests in the current study were carried out during the same dry season which eliminated seasonal variability. It cannot be ascertained in the current study if the dry season influenced the accuracies of the RDTs in a study conducted in Burkina Faso. Bisofi et al. had found a significant effect of seasonality in the discriminatory accuracy of RDT. It was reported that while the sensitivity and specificity of the RDT were 86% and 90% respectively in the dry season, the figures were 94% and 78% respectively in the rainy season , but theMalaria RDTs are generally designed to be used in malaria-endemic areas where good-quality microscopies are out of reach. It is a requirement that a diagnostic method must be accurate and available at the point of care if the effective diagnosis of all malaria cases is to be achieved. A diagnostic test with a high degree of sensitivity usually has a low false negative rate which ensures that only a few true cases are not correctly classified. It is, therefore, imperative that a screening test used in ruling out cases should have a reasonably high degree of sensitivity. In the same vein, a diagnostic test with a high degree of specificity produces low false positive rates which invariably leads to only a few misdiagnosed subjects. A confirmatory test used in ruling-in cases should have a high degree of specificity.P. falciparum and against the P. vivax, which must be at least 75% in both cases and that the false positive rates and invalid rate should be less than 10% and 5%, respectively [There is a need to adhere to the WHO recommendations on the procurement of malaria RDTs  as well This study found that the discriminatory accuracy of RDT used during the 2015 MIS survey was not strong enough. Also, the predictive accuracy, especially the positive predictive value of the RDTS, were low although the quality for RDT and microscopy used during the survey were not assessed in this study. These measures of accuracies differed across the age of the children, level of anaemia, recent experience of fever, rural–urban as well as geographical differences in the location of residence. The discriminative and predictive accuracy of a diagnostic test is a function of both the clinical diagnostic pathway and the costs of outcome misclassification. There is a need to improve on the accuracy of RDTs among this vulnerable population sub-group although the PPVs are functions of the malaria prevalence in the studied population.Despite the challenges and inadequacies in the accuracies of RDTs in both the ability to discriminate positive and negative cases and to also predict who actually has malaria, the RDTs remained the best option especially in areas with limited access to microscopy. Therefore, there is a need to improve the performance of the RDTS. Given the wide gap between the malaria prevalence from the two procedures used in the 2015 MIS, the weak discriminatory accuracy and the rather weaker predictive accuracy of the RDTs and the fact that RDTs play important role in the improvement of malaria diagnoses and consequent management of malaria, it is recommended that two different sets of RDTs should be used in the field. Similar advocacy has been made earlier in other settings . The autDue to the secondary data used in this study, the choices of explanatory variables were limited. The author could not assess the quality of the RDT and microscopy test used in the survey due to logistic constraints. The levels of the quality of the test procedures might have affected the diagnosis outcomes and the results. Although the report of the MIS study design stated that the microscopy handlers were experts who were well trained, their performances may differ and affect the microscopy test results. Also, the current study cannot ascertain whether molecular methods were used during the MIS. Regardless of these limitations, the use of nationally representative household data for this analysis makes the findings in this study generalizable in Nigeria. This is supported by an assertion that “household surveys are important tools for monitoring the malaria disease burden and measuring the impact of malaria control interventions with parasite prevalence as the primary metric” . Also, tAdditional file 1. The ROC and Lorenz curve of the accuracy of RDT test against the Microscopy test in the Nigeria 2015 MIS.


Cerebral malaria is one of the most common causes of non-traumatic encephalopathy. A 25-year-old man who is a known intravenous and oral drug abuser presented to our clinic with fever and sore throat for two days prior and an altered level of consciousness for one day. On examination, the patient was icteric, and his Glasgow coma scale score on arrival was 10/15; he had dilated pupils reactive to light and a positive corneal reflex. All cranial nerves were intact; however, signs of meningeal irritation were positive. Motor examination showed an increased tone and rigidity in all limbs, patellar reflex was 3+, plantars were down-going, and clonus was negative. A fundoscopic examination was unremarkable. Additional investigations revealed he was positive for Plasmodium falciparum, HIV, hepatitis B, and hepatitis C. In addition, a test of his cerebrospinal fluid revealed evidence of cerebral malaria. We initiated artemether 120 mg, intravenous ceftriaxone 2 g, and 5% dextrose saline for the intermittent hypoglycemia. The patient’s condition eventually improved drastically. This case outlines the possible exacerbating effect of HIV on malaria, and it calls for HIV screening and staging alongside suspected malaria. This case also underlines the need for further evaluation of a potential protective role of hepatitis B and C to find an alternative therapeutic cure for malaria. Plasmodium falciparum malaria cases were due to the involvement of the central nervous system [P. falciparum in a patient with HIV, hepatitis B, and hepatitis C, and we explore the potential influence of those concomitant infections on the patient’s cerebral malaria.Malaria is an important parasitic disease, and its neurological complication, cerebral malaria, is one of the most common causes of non-traumatic encephalopathies in the world . One stus system . We repoA 25-year-old man, with no known comorbidities but with a known history of intravenous drug abuse (heroin) from the age of 18, presented with a concern of fever and sore throat lasting two days and an altered level of consciousness  lasting one day. According to the patient’s attendant, he was in his usual state of health two days prior when he developed a high-grade fever associated with a sore throat. Furthermore, patient’s attendant mentioned that he was found in an altered state of consciousness along with fecal and urinary incontinence. The patient had no history of trauma to the head as well as no positive history of seizures. There was no significant past medical or surgical history. The patient’s addiction history was positive for heroin, Hashish, and methamphetamine both orally as well as intravenously. On examination, his vital signs on arrival were as follows: blood pressure, 110/60 mmHg ; pulse, 100 bpm ; respiratory rate, 30 breaths/minute ; and temperature, 102°F . Furthermore, in his general physical exam, he was positive for jaundice and had marks of cuts on his forearm, suggesting the possibility of multiple needle insertions. His abdominal, respiratory, and cardiovascular exam results were unremarkable. His Glasgow coma scale (GCS) on arrival was 10/15. He had dilated  pupils reactive to light, as well as a positive corneal reflex. All cranial nerves were intact; however, signs of meningeal irritation were present. A motor examination showed an increased tone in all limbs, positive rigidity in all four limbs,  his  patellar reflex was 3+, his plantars were down-going, and clonus (ankle and knee) was negative. Furthermore, the results of the fundoscopic examination were unremarkable.Plasmodium falciparum. Given the patient’s  intravenous drug abuse, we also tested his viral markers and HIV status, the results of which were positive for both hepatitis B and C and HIV, with a CD4 count of 270 . Immediately, the patient was catheterized with monitoring of urine output, and a nasogastric tube was passed. The patient was started on artemether,  120 mg, delivered in six doses spaced 12 hours apart, and intravenous ceftriaxone 2 g/day for five days. The patient had low random blood glucose levels of 60 mg/dL , for which he was started on 5% dextrose saline intravenously as well. At this point, we were suspicious of many differentials such as cerebral malaria, bacterial/tuberculous/fungal meningitis, cytomegalovirus/herpes simplex virus encephalitis, drug overdose,  central nervous system (CNS) lymphoma, as well as toxoplasmosis. To arrive at a final diagnosis, we conducted a series of additional investigations. We ordered a chest X-ray and ultrasound of the abdomen, the findings of which were  unremarkable. To rule out meningitis, we did a lumbar puncture, and his cerebrospinal fluid (CSF) findings are presented  in Table We immediately did clinical laboratory testing of this patient. His laboratory test results are presented in Table However, after 10 days of treatment, the patient showed considerable improvement despite being very critical in condition. He was no longer in an altered level of consciousness, and his fever had subsided. Furthermore, his GCS improved to 15/15, and his neurological examination results were normal. His laboratory findings had also improved. The patient was discharged and referred to an HIV clinic and a hepatitis outpatient department for his viral infections; he was also referred to a rehabilitation program for his addiction.Cerebral malaria is defined as a diffuse encephalopathy with unusual focal neurologic signs. Clinically, the patient is febrile, in an altered level of consciousness with a divergent gaze and a variable tone. There are signs of meningism, but to a lesser degree than meningitis . Further3), as well as mild elevations of proteins (up to 200 mg/dL). CSF glucose levels can be low, but this should be checked cautiously as, in cerebral malaria, plasma glucose levels are already on the lower side. Hence, studies have suggested the use of the ratio of CSF glucose to serum glucose for future studies. In our patient, CSF lactate levels could not be assessed, but there was mild pleocytosis and a marked increase in protein levels; glucose levels were normal. This marked increase of proteins and mild pleocytosis can also help differentiate viral encephalitis and bacterial meningitis, respectively [Our patient was also febrile, with an altered level of consciousness and positive signs of meningism. Furthermore, hypoglycemia was also present intermittently and treated via dextrose saline administration accordingly. Our patient also had a dysconjugate gaze, with normal pupillary reflexes and corneal reflexes with a full range of eye movement. However, his fundoscopic examination was normal, and there were no episodes of seizures. In his motor exam, the planters were down going, and we could not appreciate clonus (patellar and ankle). The findings of CSF analyses in cases of cerebral malaria usually reveal characteristically elevated lactate levels, mild pleocytosis (10 to 50 cells/mmectively ,5. Furthfalciparum malaria, thereby increasing the risk of morbidity and mortality [P. falciparum, indicating a potential protective effect [The effects of HIV, hepatitis B, and hepatitis C on cerebral malaria are scarcely documented. To our knowledge, this is the only case to document cerebral malaria with all three viral infections at the same time. Literature reveals that in HIV, the inflammatory immune response in the brain and destruction of the blood-brain barrier causes an increase in the susceptibility and severity of cerebral malaria. Additionally, the poor response to pathogens impairs the body’s ability to remove the malarial infection, thereby increasing the parasitemia and leading to severe anemia . Howeverortality , whilst ortality ,9. As foe effect .Overall, the epidemiology of all the co-infections with cerebral malaria has not been profoundly studied, and our case report will raise awareness of this phenomenon. Malaria and HIV should be considered significant public health issues worldwide, with special emphasis on the Karachi, Pakistan region. In addition, future studies involving patients with cerebral malaria should be screened and staged for HIV for more valuable insight about its effect on cerebral malaria. Additional studies are needed for hepatitis B and hepatitis C to determine their effects on cerebral malaria as the data are scarce in the literature. Moreover, if either hepatitis B or C do confer a protective effect, this protective effect should be explored to determine a potential alternative therapeutic remedy for malaria.


Malaria in pregnancy is a major public health challenge, but its risk factors remain poorly understood in some settings. This study assessed the association between household and maternal characteristics and malaria among pregnant women in a high transmission area of Uganda.A nested prospective study was conducted between 6th September 2016 and 5th December 2017 in Busia district. 782 HIV uninfected women were enrolled in the parent study with convenience sampling. Socioeconomic and house construction data were collected via a household survey after enrolment. Homes were classified as modern  or traditional . Maternal and household risk factors were evaluated for three outcomes: (1) malaria parasitaemia at enrolment, measured by thick blood smear and qPCR, (2) malaria parasitaemia during pregnancy following initiation of IPTp, measured by thick blood smear and qPCR and (3) placental malaria measured by histopathology.A total of 753 of 782 women were included in the analysis. Most women had no or primary education (75%) and lived in traditional houses (77%). At enrolment, microscopic or sub-microscopic parasitaemia was associated with house type  1.29, 95% confidence intervals 1.15–1.45, p < 0.001), level of education , and gravidity . After initiation of IPTp, microscopic or sub-microscopic parasitaemia was associated with wealth index , house type , education level  and gravidity . Placental malaria was associated with gravidity , but not with household characteristics.In an area of high malaria transmission, primigravid women and those belonging to the poorest households, living in traditional homes and with the least education had the greatest risk of malaria during pregnancy. Malaria remains a major preventable cause of maternal morbidity and adverse birth outcomes in Africa, where an estimated 12.4 million pregnant women were exposed to malaria in 2010 . For preSocial and environmental factors such as wealth  and housThis study was conducted in Busia district, an area in south-eastern Uganda where malaria transmission is perennial and holoendemic. This prospective cohort study was part of a randomized controlled trial of intermittent preventive treatment of malaria in pregnancy (IPTp), which has been previously described . BrieflyAt enrolment, women received a long-lasting insecticidal net (LLIN), underwent a standardized history and examination and had blood collected for the detection of malaria parasites by microscopy and quantitative PCR (qPCR). Women were randomized (1:1 ratio) to receive IPTp with monthly sulfadoxine–pyrimethamine (SP) or monthly dihydroartemisinin–piperaquine (DP) starting at 16 or 20 weeks gestational age as previously described . FollowiWomen received all their medical care at a study clinic open every day. Routine visits at the study clinic were conducted every 4 weeks, including collection of blood for the detection of malaria parasites by microscopy and quantitative qPCR. Women were encouraged to come to the clinic any time they were ill. Those who presented with a documented fever (tympanic temperature ≥ 38.0 °C) or history of fever in the previous 24 h had blood collected for a thick blood smear. If the smear was positive, the patient was diagnosed with malaria and treated with artemether–lumefantrine. Women were encouraged to deliver at the hospital adjacent to the study clinic. Women delivering at home were visited by study staff at the time of delivery or as soon as possible afterwards. At delivery, a standardized assessment was completed including collection of placental tissue for assessment of placental malaria.var gene acidic terminal sequence with a lower limit of detection of 1 parasite/ml [Blood smears were stained with 2% Giemsa and read by experienced microscopists. A blood smear was considered negative when the examination of 100 high power fields did not reveal asexual parasites. For quality control, all slides were read by a second microscopist and a third reviewer settled any discrepant readings. Blood samples collected at enrolment and at the time of each routine visit that were negative by microscopy were tested for the presence of submicroscopic parasitaemia using a highly sensitive qPCR assay targeting the multicopy conserved asite/ml . Placentasite/ml .Data were collected in the study clinic using standardized case record forms entered into Microsoft Access. Data from the household survey were collected using hand-held computers and customized software designed and programmed to include range checks and internal consistency checks. All statistical analyses were performed using Stata version 14.1 .Exposure variables of interest included characteristics of the study participants  and their households . Principal component analysis was used to generate a wealth index based on ownership of common household items. Households were ranked by wealth scores and grouped into tertiles to give a categorical measure of socioeconomic position. House types were classified based on definitions previously developed for the study area . Modern Among 782 women enrolled in the parent study, 29 were withdrawn before a household survey could be completed resulting in 753 women included in the assessment of parasitaemia at enrolment and during pregnancy Fig. . Most woAt enrolment, 51.1% of women had malaria parasites detected by microscopy and 81.8% had malaria parasites detected by microscopy or qPCR. In multivariate analysis, women in the poorest households had a 29% greater risk of microscopic parasitaemia compared to the least poor (adjusted Risk Ratio (aRR) 1.29, 95% confidence intervals (CI) 1.07–1.55, p = 0.008). Similarly, women living in houses with traditional construction had a 41% greater risk of microscopic parasitaemia compared to women living in houses with modern construction . The strongest risk factor for microscopic parasitaemia at enrolment was gravidity, with primigravid women having almost twice the risk compared to multigravid women . The presence of airbricks or windows, level of education, and bed net ownership were not associated with microscopic parasitaemia at enrolment in multivariate analyses Table .Table 2FFollowing the initiation of IPTp, a total of 3434 monthly routine assessments were conducted during pregnancy in 723 women, of which 15.4% were positive for malaria parasites by microscopy. Of 3412 blood smears assessed for parasitaemia by microscopy or qPCR, 43.0% were positive. Among the 30 women for whom household surveys were done but who had no routine assessments after initiation of IPTp, 25 were withdrawn before delivery and 5 were followed through delivery. The prevalence of microscopic parasitaemia was highest among women living in households in the lowest two wealth tertiles, however the association was significant only when comparing the middle tertile to the least poor tertile . Living in a house with no airbricks  and lower gravidity  were also associated with an increased risk of microscopic parasitaemia during pregnancy following the initiation of IPTp  and IPTp with SP compared to DP   is a known risk factor for malaria in pregnancy due to the lack of age-associated immunity . FinallyThis study provides evidence that the risk of malaria in pregnancy in Uganda is highest among primigravid women and those belonging to the poorest households, living in traditional homes and with the least education. Alongside efforts to maintain high coverage with IPTp, LLINs and prompt and effective diagnosis and treatment, housing improvements and education initiatives could be explored as supplementary approaches to reduce malaria in pregnancy.


Malaria is one of the most important transfusion-transmitted infections (TTIs) worldwide. To prevent the occurrence of transfusion-transmitted malaria (TTM), potential blood donors with a history of malaria or travel to, or residence in, malarious areas are permanently or temporarily deferred from donating blood. The objective of the present study was to evaluate the blood donor deferrals for malaria in Iran.This descriptive cross-sectional study was conducted in the Iranian Blood Transfusion Organization (IBTO) from 21 Mar 2011 to 19 Mar 2016 (5 yr). The data were collected and extracted from IBTO comprehensive database, namely Negareh, and then recorded in a structured template form. Statistical analysis was performed using SPSS.Of the 12,790,859 blood donation volunteers, 23,084 (0.18%) were deferred due to the risk of malaria. More than 90% of malaria-deferrals were because of travel to and residence in malaria endemic areas. Among the malaria-deferred volunteers, 22,139 (95.91%) were male and 945 (4.09%) were female; 2,053 (8.89%) were permanently deferred, while 21,031 (91.11%) were temporarily deferred. The highest malaria-deferral rates were observed in South Khorasan (0.82%), Razavi Khorasan (0.79%) and Yazd (0.54%) provinces, respectively.Given the prevalence of malaria in neighboring countries (Pakistan and Afghanistan) and several provinces of Iran and the increasing human migration and movement between malaria non-endemic and endemic areas, the malaria-deferral rate might be higher than 0.18% in Iran. Thus, the changing, as well as the precise and accurate implementation of donor selection process must be considered in all blood transfusion centers of Iran. Malaria is the most important vector-borne infectious disease  was established in order to centralize blood and blood components supply , 23. TheThe rate of deferred blood donation volunteers due to malaria risk has not previously been investigated in Iran and the current research is the first study conducted, to the best of our knowledge. Thus, the objective of the present study was to evaluate the blood donor deferrals for malaria in Iran.2015, of which 632 (45.86%) were imported cases. Currently, Iran is in the elimination stage of malaria (Iran is located in the Eastern Mediterranean Region (EMR) of the WHO  and is s malaria .In this retrospective, descriptive cross-sectional study, the comprehensive database of the IBTO, namely Negareh, was used to collect and extract the data of blood donation volunteers who presented to the blood transfusion centers of the IBTO from 21 Mar 2011 to 19 Mar 2016 (5-year period). In the IBTO, the individual characteristics and interview data, as well as the results of screening tests of blood donation volunteers are entered into the Negareh software. Therefore, this software is the best and most reliable way to access, collect and extract data of blood donors. The following data were collected and extracted from the Negareh database: total number of blood donation volunteers , blood donors and deferred volunteers, as well as the total number of deferred volunteers for travelling to, or residency in, malarious areas and deferred volunteers for a past history of malaria and the blood donation volunteers’ age and sex. Finally, the extracted data were recorded in a structured template form prepared for this purpose. Statistical analysis was conducted using SPSS ver. 18.0 .During the 5-year study period, 12,790,859 blood donation volunteers were presented to the blood transfusion centers of the IBTO and 10,167,915 (79.49%) individuals successfully donated a unit of blood. Among the blood donors, 9,677,820 (95.18%) were male and 490,095 (4.82%) were female with M/F ratio 19.75:1. Of the 2,525,283 (19.74%) deferred blood donation volunteers, 23,084 (0.91%) were deferred for malaria risk. The majority of them (91.11%) were deferred because of travel to and residence in a malaria endemic area, and the remaining 2,053 (8.89%) due to a previous history of malaria. The overall rate of deferred volunteers for malaria was 0.18%. The highest malaria-deferral rate was seen in South Khorasan (0.82%), Razavi Khorasan (0.79%) and Yazd (0.54%) provinces. In contrast, the lowest malaria-deferral rate was in Ilam (0%), Ardabil (0.001%) and Kermanshah (0.002%) provinces .The trend of malaria-deferred blood donation volunteers was not shown as an ascending or descending pattern over the study period.The average age of the malaria-deferred volunteers was 34 (range 22–58) yr. Of those, 4,135 (17.91%) were in age group 25 yr or less, 15,503 (67.16%) were in group 26–45 yr, and 3,446 (14.93%) were in age group 46 yr or more. Among the malaria-deferred volunteers, 22,139 (95.91%) were male and 945 (4.09%) were female; 2,053 (8.89%) were permanently deferred, while 21,031 (91.11%) were temporarily deferred . Of the The main purpose of the blood transfusion centers is the supply of safe and adequate blood, and blood components for patients in need. Therefore, all blood donations are screened for human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis . SeveralIn Iran and most malaria non-endemic and endemic countries, the screening of blood donors for malaria is performed through interviewing , 22–24. In the present study, the malaria-deferral rate was 0.18%, while other countries have reported different values. In Estonia 0.003%, France 0.1%–0.25%, Italy 0.1%–5%, Turkey 0.24%, Canada 0.4%, Spain 0.43%, Ireland 0.6% and the United States of America (USA) 0.75%–2.9% of blood donation volunteers were deferred for malaria risk , 29. MorThe malaria-deferral rate is high in Sistan and Baluchistan (0.45%), Hormozgan (0.05%) and Kerman (0.17%) provinces as endemic areas and low in non-endemic provinces of Iran, but the highest malaria-deferral rates were observed in non-endemic provinces, including South Khorasan 0.82%), Razavi Khorasan (0.79%) and Yazd (0.54%) provinces. The higher rate might be explained by the precise and accurate implementation of donor selection and screening of blood donors in these provinces and the other non-endemic provinces such as Fars (0.32%), Bushehr (0.29%), Isfahan (0.28%) and Qazvin (0.22%)  due to t%, Razavin=10,167,915; 79.49%) and the malaria-deferral rate has no impact on blood availability in Iran. In the USA, more than 540,000 blood donations were lost due to malaria risk from 2000 to 2006  assays of temporarily malaria-deferred volunteers are necessary, done in countries such as France, England and Australia . In IranIn this study, more than 95% of malaria-deferred volunteers were male . Since oPlasmodium anti-bodies or a rapid diagnostic test (RDT) for antigen detection in combination with donor selection through interviewing is essential to prevent the occurrence of TTM and reduce unnecessary deferrals prior to deferral decision in malaria non-endemic and endemic areas of Iran, respectively.Given the prevalence of malaria in neighboring countries (Pakistan and Afghanistan) with high endemicity and several provinces of Iran  and the


Measures of malaria burden using microscopy and rapid diagnostic tests (RDTs) in cross-sectional household surveys may incompletely describe the burden of malaria in low-transmission settings. This study describes the pattern of malaria transmission in Ethiopia using serological antibody estimates derived from a nationwide household survey completed in 2015.Plasmodium antigens: four human malaria species-specific merozoite surface protein-1 19kD antigens (MSP-1) and Apical Membrane Antigen-1 (AMA-1) for Plasmodium falciparum and Plasmodium vivax. Seroprevalence was estimated by age, elevation and region. The seroconversion rate was estimated using a reversible catalytic model fitted with maximum likelihood methods.Dried blood spot (DBS) samples were collected during the Ethiopian Malaria Indicator Survey in 2015 from malarious areas across Ethiopia. Samples were analysed using bead-based multiplex assays for IgG antibodies for six P. falciparum was 32.1%  29.8–34.4) and 25.0% (95% CI 22.7–27.3) to P. vivax. Estimated seroprevalences for Plasmodium malariae and Plasmodium ovale were 8.6% (95% CI 7.6–9.7) and 3.1% (95% CI 2.5–3.8), respectively. For P. falciparum seroprevalence estimates were significantly higher at lower elevations (< 2000 m) compared to higher (2000–2500 m) . Among regions, P. falciparum seroprevalence ranged from 11.0% (95% CI 8.8–13.7) in Somali to 65.0% (95% CI 58.0–71.4) in Gambela Region and for P. vivax from 4.0% (95% CI 2.6–6.2) in Somali to 36.7% (95% CI 30.0–44.1) in Amhara Region. Models fitted to measure seroconversion rates showed variation nationally and by elevation, region, antigen type, and within species.Of the 10,278 DBS samples available, 93.6%  had valid serological results. The mean age of participants was 15.8 years and 53.3% were female. National seroprevalence for antibodies to P. malariae and P. ovale may require programmatic attention. The use of a multiplex assay for antibody detection in low transmission settings has the potential to act as a more sensitive biomarker.Using multiplex serology assays, this study explored the cumulative malaria burden and regional dynamics of the four human malarias in Ethiopia. High malaria burden was observed in the northwest compared to the east. High transmission in the Gambela and Benishangul-Gumuz Regions and the neglected presence of The online version of this article (10.1186/s12936-019-2874-z) contains supplementary material, which is available to authorized users. Plasmodium falciparum and Plasmodium vivax are the major documented malaria parasite species, with approximately 1.2 million P. falciparum cases and 678,000 P. vivax cases reported in 2015  carbodiimide hydrochloride) and 5 mg/mL sulfo-NHS (sulfo N-hydroxylsulfosuccinimide) and incubating with rotation for 20 min at room temperature (RT), while protected from light. After a wash with coupling buffer (50 mM 2-(4-morpholino)-ethane sulfonic acid, 0.85% NaCl at pH 5.0), antigens were coupled to beads in the presence of a coupling buffer for 2 h at a concentration of 20 ug/mL for all antigens, except for PvAMA1 and GST at 15 ug/mL. Beads were washed once with PBS and suspended in PBS with 1% bovine serum albumin (BSA) with incubation for 30 min at RT by rotation. Beads were then resuspended in a storage buffer  and stored at 4 °C. Coupled beads were run with a panel of known malaria seronegatives to assure minimal non-specific MFI signal would be given by beads used in this study.All antigens were coupled to magnetic beads  as per prior studies , 21. Bri3), a bead mix was prepared with all coupled bead regions included (approximately 625 beads/antigen per well), and 50 uL bead mix was pipetted into each well of a BioPlex Pro plate . Beads were washed twice with 100 µL PBS with Tween (PBST), and 50 µL of the reagent mix  was added to each well. Negative control samples and a dilution curve of hyperimmune serum were added to each assay plate to monitor any change in control values over the course of the study. Samples of blood eluted from DBS were added to predefined wells  at 1:50 dilution. Plates were incubated overnight with gentle shaking at RT and protected from light. The next morning , plates were washed three times, and beads were re-suspended with 100 µL PBS and read on a MAGPIX machine . Mean fluorescence intensity (MFI) signal was generated for a minimum of 50 beads/region, and the background (bg) MFI from wells incubated with Buffer B was subtracted from each sample to give a final value of MFI-bg. Minimal variation was seen in the assay signal for the background or positive hyperimmune serum curve values, so no plates were re-run for the study.The DBS elution was assayed for IgG antibodies using bead-based multiplex technology, and all wash steps were performed with a handheld magnet. In 5 mL of reagent buffer  by the FMM procedure with normal distribution and maximum likelihood estimation outputs. A seropositivity cutoff value was determined by the mean MFI-bg value of the first (assumed seronegative) component plus three standard deviations   of males compared to 23.6% (95% CI 21.1–26.3) of females were seropositive .For children under 5 years of age, 18.0% (95% CI 16.1–20.1) and 14.8% (95% CI 12.7–17.2) were seropositive for P. falciparum than P. vivax, although the difference was significant in both Plasmodium species (p < 0.05).The DBS sample collection was purposely biased towards children under 5 years of age, with 44.8% (95% CI 43.0–46.5) of the DBS samples having been collected from this age group. Seropositivity increased with age group. This pattern was more pronounced for P. malariae and 1.5% (95% CI 1.1–2.0) for P. ovale using the conservative approach to define seropositivity. Both species were observed in all the regions, albeit with a variable distribution. The proportion of seropositives was slightly lower for both species, accordingly to the conservative estimation method. A similar trend of seropositivity was observed for children under 5 years of age  in Somali to 65.0% (95% CI: 58.0–71.4) in Gambela Region and for P. vivax from 4.0% (95% CI: 2.6–6.2) in Somali to 36.7% (95% CI: 30.0–44.1) in Amhara Region.The proportion of individuals seropositive was variable by region, with ons Fig. . The proP. falciparum API showed greater association with PfMSP-1 [Rho of 0.37 and p < 0.01 (spearman correlation)] and P. vivax API with PvAMA-1 (Rho 0.32 and p < 0.01).The API data from 2014 (API 2014) obtained from the Federal Ministry of Health  areas having significantly higher seroprevalence compared to areas of higher elevation (2000–2500 m) . The highest seropositivity was observed for P. falciparum at elevations below 1500 m and a peak was observed at an elevation below 1000 m , p > 0.05). Among children under 5 years of age, P. falciparum and P. vivax both showed a significant although varying relationship with elevation. Plasmodium vivax showed direct relation with increasing elevation. High P. vivax seropositivity was observed at higher elevations above 1500 m .Seropositivity was inversely related to elevation for P. falciparum and P. vivax. Higher seropositivity is predicted in the northwest compared to the southeast.Generally, seropositivity was found to vary in space, with elevation and among administrative regions, as depicted in Fig. P. falciparum and P. vivax are shown in Fig. P. falciparum compared to P. vivax both for the combined MSP-1/AMA-1 outcome and individual MSP-1 and AMA-1 antigens; and MSP-1 antigen show higher seroconversion rates compared to AMA-1 antigens for both species. Heterogeneity was observed across the different antigen responses. A similar trend was observed when the model was fitted to data with elevation below 2000 m and combined MSP-1 and AMA-1 antigens. Regionally, the seroconversion model was fitted to the four major administrative regions  both for P. falciparum and P. vivax MSP-1 and AMA-1 antigen responses. Heterogeneous seroconversion rates were observed over the regions .The overall age seroconversion plot for antibody responses for both P. falciparum MSP-1 or AMA-1 antigens, and 25.0% for P. vivax MSP-1 or AMA-1. The relative numbers were lower for children under 5 years of age at 18.0% for P. falciparum and 14.8% for P. vivax, suggesting a lower recent transmission in Ethiopia. Seropositivity in children under 5 years of age may accurately represent recent infection as they have had limited exposure and time to generate the cumulative antibody response seen in adults [Plasmodium, of which 0.5% was due to P. falciparum.The current study documented malaria seroprevalence in Ethiopia using samples collected from a national EMIS conducted in 2015. Of all samples analysed, 32.1% had IgG antibodies against combined n adults –26. The n adults , 27–29. P. falciparum transmission were observed in areas of lower elevation (< 2000 m). This is consistent with previous studies [Anopheles vector mosquitoes [P. vivax seropositivity with elevation over the range of the study setting could expand the understanding of malaria transmission in Ethiopia. The relapse of P. vivax infections may have contributed to the high P. vivax prevalence observed at higher elevations [Generally, significantly higher levels of  studies , 17, 19,squitoes . This reevations –35. Travevations –26, but evations .P. falciparum and P. vivax. Increased malaria risk in men in Ethiopia has been attributed to a greater extent of outdoor, occupational exposure [Seropositivity was high for children under 5 years of age, particularly in the Gambela and Benishangul Gumuz Regions, although was lower than in adults. These show higher malaria transmission that may need a more intensive approach for malaria control in the affected areas. A larger proportion of males than females were seropositive for both exposure –27, 36.P. malariae and 3.1% for P. ovale. Variable trends of proportion seropositive were observed in the regions for both species. These findings, albeit with high proportion, support previous reports of sporadic occurrence of P. malariae and P. ovale that may be responsible for up to 1% of the malaria incident cases in Ethiopia [Plasmodium species, P. malariae and P. ovale, in Ethiopia. Antibody cross-binding among the different MSP-1 antigens has been documented as non-substantial [P. malariae and 1.5% for P. ovale, with the regional trend and pattern of transmission remaining similar.A total of 8.6% of individuals were seropositive for Ethiopia , 37–40. stantial , 41. In The use of serological methods in measuring malaria transmission in low-transmission settings has been documented in a number of studies , 42, 43.P. falciparum and P. vivax, respectively, for the Amhara region in 2013 [P. falciparum and 25.0% for P. vivax for the same region. The slight variation in seropositivity may be attributed to the different type of laboratory assay used. The challenge of comparing data from ELISA and bead-based multiplex serology has been investigated previously [P. falciparum, although Cook et al. [P. falciparum in low-transmission settings. Characterization of antigen markers may be required to further qualify the serology methods [The findings show the magnitude of transmission intensity was highly variable among different regions and elevations in Ethiopia. Yalew et al. reported similar trends with 30.0 and 21.8% seroprevalence for  in 2013 . The cureviously . Resultseviously . Heterogeviously  describek et al.  reported methods . The curThe study had several limitations. Only 65% of DBS samples from the EMIS-2015 survey were available for serological analysis. Although no systematic bias was introduced and frequencies were weighted, the representativeness of this sample at the national and regional levels should be interpreted cautiously. The data were insufficient to produce refined spatial heat maps and the maps produced show only general trends. Samples collected are assumed to reflect the malaria exposure of their respective locations and did not account for potential population movement. Although the survey reported very low recent travel history, past travel encompassing the previous harvest season as well as previous years were not captured and could reflect past malaria exposure risk from a different locale. This study assessed long-term markers of transmission, but further characterizing antigens based on local eco-epidemiology is recommended to identify and select specific short- and long-term markers.P. vivax seropositivity with elevation and the presence of P. malariae and P. ovale in all administrative regions  may require programmatic consideration in selecting diagnostic tools and appropriate treatment guidelines. These results can be used as baseline data to evaluate the recent malaria elimination efforts in Ethiopia especially as routine surveillance systems are progressively being strengthened.The current study explored the malaria burden and transmission intensity using serological markers of exposure to four malaria species. It documented the magnitude, spatial distribution and dynamics of transmission over differing elevation, administrative regions, and age groups using samples collected during a national programme evaluation survey with minimal sample preparation time and cost. These findings confirmed the National Malaria Control Programme data of the relative high transmission in the Gambela and Benishangul-Gumuz Regions and highlighted gaps in the current understanding of malaria epidemiology. The increase of Additional file 1. Percent malaria seropositivity and Odds Ratio (OR) by sex, age and elevation for each species in malaria endemic areas of Ethiopia, 2014.Additional file 2. An Interpolated surface map for P. falciparum (left) and P. vivax (right). Empirical bayesian kriging was used to produce the maps from the Annual Parasite Incidence data in Ethiopia (API 2014).Additional file 3. Regional age-seroconversion plots for antibody responses for Plasmodium falciparum antigens. Y-axis represents probability of being seropositive and the X-axis age. Seroconversion curves represent the rate at which a population become seropositive to specific antigens resulting in seroconversion rates (SCR) or lambda (λ). In each graph points represent age seroprevalence (by deciles), unbroken line represents maximum likelihood curves and broken lines represent the 95% confidence interval. Plots A and B depict the seroconversion curves for P. falciparum antigens response to MSP-1 (A) and AMA-1(B) for the major four regions Tigray, Amhara, Oromia and Southern Nations and Nationalities People’s Regions.Additional file 4. Regional age-seroconversion plots for antibody responses for P. falciparum antigens. Y-axis represents probability of being seropositive and the X-axis age. Seroconversion curves represent the rate at which a population become seropositive to specific antigens resulting in seroconversion rates (SCR) or lambda (λ). In each graph points represent age seroprevalence (by deciles), unbroken line represents maximum likelihood curves and broken lines represent the 95% confidence interval. Plots A and B depict the seroconversion curves for P. vivax antigens response to MSP-1 (A) and AMA-1 (B) for the major four regions, Tigray, Amhara, Oromia and Southern Nations and Nationalities People’s Region (SNNPR).


Azithromycin has activity against malaria parasites, and malaria is a leading cause of child mortality in the Sahel. The effect of biannual versus annual azithromycin distribution for trachoma control on serological response to merozoite surface protein 1 . Communities were treated for 36 months (6 versus 3 distributions). Dried blood spots were collected at 36 months among children ages 1–5 years, and MSP-119 seropositivity was 62.7% in the biannual distribution arm compared to 68.7% in the annual arm . Mean semi-quantitative antibody levels were lower in the biannual distribution arm compared to the annual arm .Antibody results were available for 991 children. MSP-1Targeted biannual azithromycin distribution was associated with lower malaria seroprevalence compared to that in a population that received annual distribution.Trial Registration Clinicaltrials.gov NCT00792922 Biannual mass azithromycin administration has been shown to decrease all-cause post-neonatal child mortality in some settings in sub-Saharan Africa , 2. AnnuPlasmodium falciparum, the most virulent human malaria parasite, due to action against the parasite apicoplast [Azithromycin has modest activity against icoplast –17. Previcoplast . Previouicoplast . Howevericoplast , 19. Theicoplast . AlternaP. falciparum, is predicted to provide information about malaria incidence beyond point prevalence by integrating serologic responses at different time points [P. falciparum exposure in preschool-aged children in Niger.Antibody measurements have been proposed as markers of malaria exposure over time –23. Popue points –25. While points , 25. HerEthical approval was obtained from the Committee on Human Research at the University of California, San Francisco and the Comité d’Ethique du Niger. Verbal informed consent was obtained from local chiefs of each study community and from the parent or guardian of each study participant. CDC staff did not have contact with study personnel or access to personal identifying information and were determined to not be engaged in human subjects research.PRET was a series of community-randomized trials in Niger, The Gambia, and Tanzania designed to assess mass azithromycin distribution strategies for trachoma control . In the present report, data from the Niger trial only were included –28. The Study communities were located in Matamèye District, Zinder Region and were treated from May 2010 until May 2013. This region is situated in the Sahel and has highly seasonal malaria incidence, with peak transmission shortly after the peak in rainfall, typically in September , 30. At Prior to each MDA, a door-to-door enumerative census was undertaken in all study communities, which formed the sampling frame for treatment and evaluation. In all communities included in this report, each MDA occurred over a 1-to-4-day period: up to three follow-up visits occurred after the initial MDA day in an attempt to achieve coverage of 90% or greater. In the annual MDA arm, communities received a total of three rounds of MDA distributed via a door-to-door program to all individuals, regardless of age. In the biannual MDA communities, children aged 6 months to 12 years received a total of six rounds of door-to-door MDA; no one over the age of 12 was treated in these communities. During each MDA, all eligible participants were offered a single dose of directly observed oral azithromycin (20 mg/kg up to a maximum dose of 1 g in adults). Children under 6 months of age or those with macrolide allergy were offered topical tetracycline ointment (1%) for 6 weeks. In the annual treatment arm, pregnant women were offered tetracycline ointment.P. falciparum antigen MSP-119 using a multiplex bead array assay on a Luminex 200 platform. Results were reported as the median fluorescence intensity (MFI) minus background (MFI-BG), where background is the signal from beads with buffer only. The seropositivity cutoff was MFI-BG ≥ 1758 as determined by receiver operator characteristic curve analysis using a positive panel of serum from individuals with malaria slides positive for P. falciparum and a negative panel of serum from US-residents who had never travelled to a malaria-endemic region.In each study community, a random sample of 50 children aged 0 to 5 years were selected to have samples collected. Dried blood spots were only collected in children age 1 to 5 years of age due to the presence of maternal antibodies. Blood samples were collected via finger or heel stick in September 2013. Dried blood spots based on the most recent census  were anaP. falciparum infection using microscopy. Thick blood smears were stained with 3% Giemsa, and each slide was read by two experienced microscopists at the Zinder Regional Hospital. Discrepancies were adjudicated by a third reader. Microscopists determined the presence or absence of P. falciparum parasites and counted the number of asexual parasites per 200 white blood cells (assuming a white blood cell count of 8000/μl). Each child’s tympanic temperature was assessed at the time of blood collection. Clinically symptomatic malaria was defined as a blood slide positive for P. falciparum accompanied by tympanic temperature ≥ 38.5 °C. The geometric mean of the two parasite densities was used for analysis. Haemoglobin concentration was measured for all children .Blood samples from the children who contributed dried blood spots were also tested for The trial was powered for the primary trachoma outcome . An a pr10 transformations of MFI-BG (as a semi-quantitative indicator of antibody levels) and parasite density was used for analysis. Parasite prevalence, clinically symptomatic malaria prevalence, and seroprevalence of MSP-119-specific antibodies and corresponding binomial 95% confidence intervals (CI) were calculated at the community level. Prevalence ratios (PR) for the association between malaria infection and MSP-119 seropositivity were calculated using generalized linear mixed models with a binomial distribution and log link with a random effect for the study community to account for clustering within communities, and adjusted for age and gender [All analyses were conducted as intention-to-treat. Descriptive statistics were calculated by study arm with medians and interquartile ranges (IQR) or proportions. A logd gender , 33.10 transformation of the MSP-1 MFI-BG values was used. Generalized linear mixed models with a Gaussian distribution and identity link were used to estimate the mean difference in antibody level between study arms, with a random effect for study community. Differences in the age-seroprevalence and semi-quantitative antibody curves were evaluated to assess differences in short- and long-term malaria exposure in a generalized linear model with binomial (seropositivity) or Gaussian (MFI-BG) distribution, with a study arm by age category interaction term, with age treated as a continuous variable. All analyses were conducted in R .To assess the difference in seropositivity to MSP-1 by study arm, generalized linear mixed model with a binomial distribution and log link were used to estimate risk ratios, with a random effect for study community. To assess differences in quantitative antibody levels, a log19 serologic data, of whom 460 were in annual azithromycin distribution communities and 531 in biannual azithromycin distribution communities . The prevalence of malaria infection and seropositivity increased with increasing age , but the prevalence of clinically symptomatic malaria did not . Figure 19 titre. MSP-119 seropositivity was higher among children with malaria infection  compared to those without infection, but not among those with clinically symptomatic malaria  compared to those without clinically symptomatic malaria.In September 2013 at the 36-month study visit, half of the children  had a positive thick smear for malaria parasites, and prevalence of malaria was 7.0% (95% CI 5.5 to 8.7%). As previously reported, there were no significant differences in malaria infection or clinically symptomatic malaria prevalence by study arm , 19. Ser19 seroprevalence was 9% lower  among 1–5-year-olds from communities in which children received biannual treatment compared to those from communities receiving annual treatment. Mean MFI-BG was also lower in 1–5-year-olds in biannual MDA communities than children in communities receiving annual MDA   between children in communities receiving biannual versus annual azithromycin.MSP-1P. falciparum compared to annual distribution to the entire community. In these same communities, no difference in P. falciparum infection prevalence after 36 months of treatment was reported [19 is long-lived [Biannual distribution of azithromycin targeted to children was associated with lower antibody-based measures of exposure to reported . The antng-lived  and is p19 seroprevalence documented in this study between biannually and annually treated communities diverges from previous reports that have indicated a 44 to 73% decrease in malaria infection prevalence 1 month after azithromycin treatment [P. falciparum exposure would be expected since the outcomes reflect differences in cumulative exposure between groups, averaged over a longer period of time. However, the intensity of transmission in holoendemic regions may make it difficult to detect differences in malaria seropositivity, particularly as children age and their probability of previous exposure increases. In holoendemic settings, short-acting interventions may also have less effect on transmission due to the ubiquity of infection. Among young children in particular, antibody responses may be lost, which could affect sensitivity to seasonal trends [The small (9%) reduction in MSP-1reatment . Comparel trends , 36. TheP. falciparum due to targeting the plasmodial apicoplast [Campylobacter species, an important cause of diarrhea and diarrhea-related mortality, was reduced in children in communities receiving biannual azithromycin compared to placebo in Niger [Azithromycin has modest in vitro activity against icoplast , 16, 37,icoplast , 13, 38.icoplast , 40. Addicoplast . Azithroin Niger . Any effThe results of this study must be considered in the context of several limitations. First, there was no untreated control group, and thus the quantitative impact of azithromycin distribution cannot be determined. Second, biannual treatment of children under age 12 was compared to annual treatment of all individuals in the community, and so did not compare biannual versus annual treatment in the same age group. Third, mass azithromycin distributions occurred at the beginning of the high transmission season and the low transmission season. Malaria transmission is highly seasonal in Niger, and treatment targeted specifically during the high transmission season may have had a larger effect than treatment during the low transmission season. However, a single dose of azithromycin during the high transmission season may also paradoxically have reduced effect compared to treatment during the low transmission season due to the high parasite load and frequency of infection during the high transmission season . Fourth,P. falciparum exposure in communities in Niger receiving targeted biannual azithromycin in children compared to those receiving annual azithromycin distribution to entire communities. Thus, mass treatment with azithromycin may lead to a decrease in malaria incidence in young children, presumably contributing to the survival benefits afforded by azithromycin.The results of this study are consistent with a small reduction in


A nationwide, school, malaria survey was implemented to assess the risk factors of malaria prevalence and bed net use among primary school children in mainland Tanzania. This allowed the mapping of malaria prevalence at council level and assessment of malaria risk factors among school children.(1) August to September 2014; (2) May 2015; and, (3) October 2015. Children were tested for malaria parasites using rapid diagnostic tests and were interviewed about household information, parents’ education, bed net indicators as well as recent history of fever. Multilevel mixed effects logistic regression models were fitted to estimate odds ratios of risk factors for malaria infection and for bed net use while adjusting for school effect.A cross-sectional, school, malaria parasitaemia survey was conducted in 25 regions, 166 councils and 357 schools in three phases: In total, 49,113 children were interviewed and tested for malaria infection. The overall prevalence of malaria was 21.6%, ranging from < 0.1 to 53% among regions and from 0 to 76.4% among councils. The malaria prevalence was below 5% in 62 of the 166 councils and above 50% in 18 councils and between 5 and 50% in the other councils. The variation of malaria prevalence between schools was greatest in regions with a high mean prevalence, while the variation was marked by a few outlying schools in regions with a low mean prevalence. Overall, 70% of the children reported using mosquito nets, with the highest percentage observed among educated parents (80.7%), low land areas (82.7%) and those living in urban areas (82.2%).The observed prevalence among school children showed marked variation at regional and sub-regional levels across the country. Findings of this survey are useful for updating the malaria epidemiological profile and for stratification of malaria transmission by region, council and age groups, which is essential for guiding resource allocation, evaluation and prioritization of malaria interventions.The online version of this article (10.1186/s12936-018-2601-1) contains supplementary material, which is available to authorized users. The altitude was extracted for the geo-location of the schools, using data from Shuttle Radar Topography Mission . The malaria prevalence was 18.2% in children 5 to < 9 years (95% CI 16.1–20.5%), 21.4% in children aged 9–12 years (95% CI 19.2–23.8%) and 23.3% in children older than 12 years (95% CI 21.2–25.7%). The malaria prevalence was highest in children reported parents with no school education , compared to children with reported parents with primary , reported parents with secondary , and reported parents to have higher education . In meso-endemic, and hyper-holo-endemic councils almost one-third of the children were tested malaria positive , in hypo-endemic councils only 10% were tested positive , and in low stable endemic councils fewer than 2% were tested positive   tested positive for malaria (95% CI 19.5–23.9) , and in children with parents with secondary or higher education 0.75 (95% CI 0.67–0.83), compared to children with parents with primary education. The odds ratios of bed net use increased with increasing education of the parents. Children with non-educated parents had an odds ratio of 0.69 (95% CI 0.63–0.76), with secondary or higher education was 1.48 (95% CI 1.35–1.61), compared to children reported to have parents with primary education.In comparison to children living in the Central Zone, children living in Northern and Southern Highlands had lower odds of malaria infection, and children living in the other zones had higher odds of malaria infection. For instance, children living in the Lake Zone had 24.4 times higher odds of malaria infection compared to children living in the Central Zone (95% CI 10.4–57.1). Children living in Southern Highlands and Northern Zones, were less likely to sleep under a bed net , while higher odds ratios were found in children living in the Lake Zone , compared to children living in the Central Zone. The odds of malaria infection significantly decreased at higher altitudes, with an odds ratio of 0.26 at 750–1250 m (95% CI 0.11–0.62), an odds ratio of 0.25 at 1250–1750 m (95% CI 0.09–0.72) and an odds ratio of 0.07 at altitudes higher than 1750 m (95% CI 0.01–0.47), compared to areas below 750 m. The odds for children to sleep under a bed net decreased significantly with increasing altitude .–0.29). Children living in urban councils were two times more likely to sleep under a bed net than children living in rural councils .Living in urban councils was significantly associated with lower odds of malaria infection, compared to living in rural councils , moist deciduous forest areas , mountain system , and three times higher in rainforest areas  compared to scrubland areas. Regarding bed net use, children in tropical rainforest areas were more likely to use a bed net , while children in moist deciduous forest were least likely to use a bed net , in comparison to tropical scrubland areas (Table –42.4), Southern Zone , as well as Western Zone , and lowest in Central , and Northern zones . At council level, the malaria prevalence ranged from 0 to 76.4%. In 62 of the 166 councils, the malaria prevalence was below 5%, in 27 between 5 and 10%, in 25 between 10 and 25%, in 51 between 25 and 50%, and in 18 councils above 50%. Highest malaria prevalence was found in Geita, Pwani, Mwanza, and Katavi (≥ 40%); lowest prevalence in Arusha, Kilimanjaro, Manyara and Iringa (< 1%)  and in the southeast lowlands of Tanzania. The geographical pattern was similar to the previously described geographical pattern of malaria prevalence and vulnerability , 45. ComThe percentage of reported bed net ownership in the children’s household was much higher than the reported percentages in the TDHS-MIS (89 vs 65%). However, the trend among regions was similar, with lower percentages in the middle part of Tanzania and higher percentages in regions in the Lake Zone and Southern Zone of Tanzania. The high reported bed net ownership among school children could likely be influenced by recall, reporting or interviewer bias, leading to overestimated values, although it was found that school children give reliable answers about bed net coverage in their community . The perThe small increase in the malaria prevalence by age at all transmission zones, as well as the lack of significant association between age and malaria, might be surprising. Whilst the proportion of children with malaria slightly increased by age in all transmission zones, it would have been expected that younger children have a higher prevalence in high transmission areas and that older children would have a higher prevalence in low transmission zones . A signiConsidering the variety of putative risk factors for malaria and bed net use, the regression models were not fully adjusted and in future analysis, it would be interesting to include risk factors such as distance to nearest health facility, distance to nearest water body, population density, housing conditions and/or socio-economic status. Also, the model included TSI and altitude, which were correlated but remained significant in the multivariable log-likelihood ratio test. Children, excluded in model I, adjusted for education and eco-zone had significantly higher reported bed net use and were on average younger than the children included in the model. One possible reason for the higher percentage of bed net use in the excluded children would be the school net distribution campaign in Southern Tanzania  in 2013 . This woMalaria rapid diagnostic tests were used to test children for malaria, which may have led to an overestimation in high transmission areas since the RDT were found to be limited in their ability to distinguish between “active and resolved infections” . Also, aSelf-reported values are likely to differ from the truth, depending on interviewer and respondent characteristics, and face-to-face interviews are more likely to lead to answers influenced by social expectations , 58. SinThe data were analysed without adding sampling weights to account for the varying probability of selection at sub-council level. Nevertheless, with respect to representativeness, the study design included a population-weighted selection of council and stratum. In addition, the lack of available data at sub-council level to determine sampling weights would have provided limited additional accuracy to the results. Another limitation of the representativeness would be school absenteeism at day of the survey, drop out and enrolment rates in schools. According to a national educational survey conducted in 2013, enrolment rates were lowest in Kigoma, Katavi and Manyara regions , and otherwise mostly above 90% . School The SMPS, as all cross-sectional surveys, captures malaria infection prevalence only at a certain time point and seasonal variations are inevitable. In the middle corridor, with low malaria prevalence, the survey was conducted during the end of wet season in most of the councils, while around the Lake Zone and in the southern parts of the country, with high malaria prevalence, the survey was conducted during the beginning of the short rains and dry seasons. The authors acknowledge that in Tanzania there is no quantifiable way to adequately and entirely adjust for differences in timing of the survey with expected prevalence rate, and this is a challenge even in most sophisticated mapping models or malaria prevalence. However, most school children 5–16 years), including those in this study, carry asymptomatic infections  years, i, 61, potThis SMPS, which is powered with adequate sample size to provide malaria prevalence estimates at council and sub-council levels, provides a complementary approach to malaria surveillance and parasitological monitoring in a short period of time alongside with other national representative surveys, such as Tanzania DHS and MIS. The nationwide school survey is the first survey in Tanzania describing the malaria risk among school children and the geographical trend. This is of importance for malaria control and elimination, as malaria infections in school children are often asymptomatic, contributing to malaria transmission in the community as ‘hidden’ parasite reservoirs . The SMPThe observed overall malaria prevalence of 21.6% ranging from < 0.01  to 53.6% (Geita) among regions indicates similar malaria heterogeneity and patterns as reported in the national surveys (TDHS/MIS). Findings of this survey are useful for updating the malaria epidemiological profile and for stratification of the malaria transmission by region, council and age groups, which is essential for guiding resource allocation and prioritizing future malaria interventions.Additional file 1: Fig. S1. Flow chart of sampling design.Additional file 2: Fig. S2. Duration of data collection in days per survey phase and district.Additional file 3: Fig. S3. Age histogram.Additional file 4: Fig. S4. Malaria prevalence per age by transmission zone.Additional file 5: Fig. S5.A Map of the observed prevalence among schools aggregated per council, separated by survey phase. B Boxplot showing the distribution of observed prevalence among schools per region, sorted by amount of rainfall in the 3 months preceding the survey and separated by survey phase.