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Biological sciences, drug discovery and medicine rely heavily on cell phenotype perturbation and observation. Aside from dramatic events such as cell division or cell death, most cell phenotypic changes that keep cells alive are subtle and thus hidden from us by natural cell variability: two cells in the same condition already look different. While we show that deep learning models can leverage invisible features from microscopy images, to discriminate between close conditions, these features can yet hardly be observed and therefore interpreted. In this work, we show that conditional generative models can be used to transform an image of cells from any one condition to another, thus canceling cell variability. We visually and quantitatively validate that the principle of synthetic cell perturbation works on discernible cases such as high concentration drug treatments, nuclear translocation and golgi apparatus assays. We then illustrate its effectiveness in displaying otherwise invisible cell phenotypes triggered by blood cells under parasite infection, the presence of a disease-causing pathological mutation in differentiated neurons derived from iPSCs or low concentration drug treatments. The proposed approach, easy to use and robust, opens the door to the accessible discovery of biological and disease biomarkers.

BackgroundMany SARS-CoV-2 seroprevalence surveys since the end of 2020 have disqualified the first misconception that Africa had been spared by the pandemic. Through the analysis of three SARS-CoV-2 seroprevalence surveys carried out in Benin as part of the ARIACOV project, we argue that the integration of epidemiological serosurveillance of the SARS-COV2 infection in the national surveillance package would be of great use to refine the understanding of the COVID-19 pandemic in Africa.MethodsThree repeated cross-sectional surveys have been carried out in Benin, two in Cotonou, the economic capital in March and May 2021, and one in Natitingou, a semi-rural city in North in August 2021. The global and by age-groups weighted seroprevalences have been estimated and the risk factors of the infection by SARS-COV-2 have been assessed by using logistic regression.ResultsIn Cotonou, a slight increase in overall age-standardized SARS-CoV-2 seroprevalence from 29.77% (95% CI: 23.12-37.41%) at the first survey to 34.86% (95% CI: 31.57-38.30%) at the second survey was observed. In Natitingou the global adjusted seroprevalence was 33.34% (95% CI: 27.75-39.44%), much higher than expected. Adults over 40 seemed to be more at risk than the youngest during the first survey in Cotonou but no longer in the second survey, showing the persistence of the SARS-COV-2 virus circulation outside the epidemic waves.ConclusionsA routine serological surveillance on strategic sentinel sites and / or populations could constitute a cost / effective compromise to better anticipate the onset of new waves and define public health strategies.

Background Plasmodium falciparum-infected erythrocytes bind to specific endothelial cell receptors via members of the PfEMP1 family exported onto the erythrocyte surface. These interactions are mediated by different types of cysteine-rich interdomain region (CIDR) domains found in the N-terminal region of all PfEMP1. CIDRα1 domains bind endothelial protein C receptor (EPCR), CIDRα2–6 domains bind CD36, whereas the receptor specificity of CIDRβ/γ/δ domains is unknown. Methods In this study, we investigated the level of immunoglobulin (Ig)G targeting the different types of PfEMP1 CIDR during the first year of life. We used plasma collected longitudinally from children of pregnant women who had been followed closely through pregnancy. Results Antibodies to CIDRα1 domains were more frequent in cord blood compared with antibodies to CIDRα2–6 domains. Higher IgG levels to EPCR-binding CIDRα1 variants positively correlated with the timing of first infections. Antibodies to all PfEMP1 types declined at similar rates to the point of disappearance over the first 6 months of life. At 12 months, children had acquired antibody to all types of CIDR domains, mostly in children with documented P falciparum infections. Conclusions These observations agree with the notion that the timing and phenotype of first P falciparum infections in life are influenced by the immune status of the mother.

BackgroundPlacental malaria (PM) is associated with a higher susceptibility of infants to Plasmodium falciparum (Pf) malaria. A hypothesis of immune tolerance has been suggested but no clear explanation has been provided so far. Our goal was to investigate the involvement of inhibitory receptors LILRB1 and LILRB2, known to drive immune evasion upon ligation with pathogen and/or host ligands, in PM-induced immune tolerance.MethodsInfants of mothers with or without PM were enrolled in Allada, southern Benin, and followed-up for 24 months. Antibodies with specificity for five blood stage parasite antigens were quantified by ELISA, and the frequency of immune cell subsets was quantified by flow cytometry. LILRB1 or LILRB2 expression was assessed on cells collected at 18 and 24 months of age.ResultsInfants born to PM-mothers had a higher risk of developing clinical malaria than those born to mothers without PM (IRR=1.53, p=0.040), and such infants displayed a lower frequency of non-classical monocytes (OR=0.74, p=0.01) that overexpressed LILRB2 (OR=1.36, p=0.002). Moreover, infants born to PM-mothers had lower levels of cytophilic IgG and higher levels of IL-10 during active infection.ConclusionModulation of IgG and IL-10 levels could impair monocyte functions (opsonisation/phagocytosis) in infants born to PM-mothers, possibly contributing to their higher susceptibility to malaria. The long-lasting effect of PM on infants’ monocytes was notable, raising questions about the capacity of ligands such as Rifins or HLA-I molecules to bind to LILRB1 and LILRB2 and to modulate immune responses, and about the reprogramming of neonatal monocytes/macrophages.KEY POINTSInfants of mothers with placental malaria were more susceptible to clinical malaria than those born to mothers without placental malaria and they displayed a lower frequency of non-classical monocytes that overexpressed LILRB2.

Background Malaria in early pregnancy occurs at a time when the placenta is developing, with possible consequences for placental function and fetal growth. We assessed the association between first trimester malaria and fetal growth documented through repeated ultrasound scans. Methods The RECIPAL preconceptional cohort included 411 Beninese pregnant women followed from 7 weeks’ gestation (wg) until delivery. Among them, 218 had 4 scans for fetal monitoring at 16, 22, 28, and 34 wg. Multivariate seemingly unrelated regression models were used to assess association of microscopic malaria in the first trimester ( Results Of 39% (86/218) of women with at least 1 microscopic malarial infection during pregnancy, 52.3% (45/86) were infected in the first trimester. Most women (88.5%) were multiparous. There was no association between adjusted z-scores for fetal growth parameters and first trimester malaria. Parity, newborn sex, socioeconomic level, and maternal body mass index significantly influenced fetal growth. Conclusions In a context where malaria infections in pregnancy are well detected and treated, their adverse effect on fetal growth may be limited. Our results argue in favor of preventing and treating infections as early as the first trimester.

ObjectiveIn the framework of EVALMOUS study aiming to assess the use and effectiveness of mosquito nets by pregnant women and other members of their household in a lagoon area in southern Benin, the behaviour of pregnant women relative to the time they go to bed using the net were recorded. Malaria vectors biting rhythm, Plasmodium falciparum infection and insecticide resistance genes in malaria vectors were also determined.ResultsOverall, 3848 females of Anopheles gambiae s. l. were collected and 280 pregnant women responded to the survey. Almost all Anopheles gambiae s. l. tested were Anopheles coluzzi with the exception of two, which were Anopheles melas. The CSP index in malaria vector was 1.85% and the allelic frequency of kdr gene was 74.4%. Around 90% of bites and Plasmodium falciparum transmission occurred between 10 p.m. and 6 a.m., which coincides with the period when more than 80% of pregnant women were under bednet. Despite a slight early evening and early morning biting activity of malaria vectors in the study area, the good use of nets might remain a useful protection tool against mosquito biting and malaria transmission.

Background In the context of global malaria elimination efforts, special attention is being paid to submicroscopic Plasmodium falciparum infections. In pregnant, sub-Saharan African women, such infections are more prevalent than microscopic infections, and are thought to have adverse effects on both mothers’ and newborns’ health. However, no study has studied the dynamics and determinants of these infections throughout pregnancy. Retard de Croissance Intra-uterin et Paludisme (RECIPAL), a preconception cohort study carried out in Benin between 2014 and 2017, represented a unique opportunity to assess this issue. Methods We used data from 273 pregnant Beninese women who were followed-up from preconception to delivery. We studied the dynamics of and factors influencing submicroscopic (and microscopic) P. falciparum infections during the 3 trimesters of pregnancy, using an ordinal logistic mixed model. Results The incidence rate of submicroscopic P. falciparum infections during pregnancy was 12.7 per 100 person-months (95% confidence interval [CI] 10.8–14.9), compared to 6.7 per 100 person-months (95% CI 5.5–8.1) for microscopic infections. The prevalences were highest in the first trimester for both submicroscopic and microscopic infections. After adjustment for potential confounding factors, we found that those of young age and those with a submicroscopic P. falciparum infection prior to pregnancy were at significantly higher risks of submicroscopic and microscopic infections throughout pregnancy, with a more pronounced effect in the first trimester of pregnancy. Conclusions The first trimester of pregnancy is a particularly high-risk period for P. falciparum infection during pregnancy, especially for the youngest women. Malaria prevention tools covering the preconception period and early pregnancy are urgently needed to better protect pregnant women and their newborns., In a preconception malaria cohort study, the prevalence of submicroscopic versus microscopic Plasmodium falciparum infections was higher throughout pregnancy, most markedly in the first trimester, and young women with submicroscopic infections before pregnancy had a higher subsequent risk of infection.

Ultrasensitive molecular diagnostics are lowering the limit of detection for malaria parasites in the blood and providing insights not captured by conventional tools such as microscopy and rapid antigen tests. Low-level malaria infections identified by molecular tools may influence clinical outcomes, transmission events, and elimination efforts. While many ultrasensitive molecular methods require well-equipped laboratories, technologies such as loop-mediated isothermal amplification and recombinase polymerase amplification provide more portable and analytically sensitive solutions. These tools may benefit asymptomatic patient screening, antenatal care, and elimination campaigns. We review the recent evidence, offer our perspective on the impact of these new tests, and identify future research priorities.

Background Harmful maternal and neonatal health outcomes result from malaria in pregnancy, the prevention of which primarily relies on intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP). The World Health Organization recommends IPTp-SP in sub-Saharan Africa, but implementation is highly heterogeneous and often suboptimal in terms of the number of doses and their timing. In this study, we assessed the impact of this heterogeneity on malaria in pregnancy, mainly with respect to submicroscopic Plasmodium falciparum infections. Methods We used data from 273 Beninese women followed throughout pregnancy. Screening for P. falciparum infections, using both microscopy-based and polymerase chain reaction (PCR)–based methods, was performed monthly, and information on IPTp-SP doses was collected. Gestational age was estimated by repeated ultrasound scans. Using a negative binomial model, we investigated the effect of IPTp-SP doses and timing after 17 weeks of gestation on the number of P. falciparum infections, focusing on submicroscopic infections detectable only by PCR. Results At least 2 IPTp-SP doses were taken by 77.3% of the women. The median gestational age at the first IPTp-SP dose was 22 weeks. A late first IPTp-SP dose (>21.2 weeks) was marginally associated with an increased number of P. falciparum infections (adjusted incidence rate ratio [aIRR] = 1.3; P = .098). The number of IPTp-SP doses was not associated with the number of submicroscopic infections (aIRR = 1.2, P = .543). Conclusions A late first IPTp-SP dose failed to provide optimal protection against P. falciparum, especially submicroscopic infections. This highlights the need for a new antimalarial drug for IPTp that could be taken early in pregnancy., In a cohort study, increased numbers of Plasmodium falciparum infections were found in pregnant women with suboptimal dose numbers and late first doses of intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP). The timing of IPTp-SP primarily affects submicroscopic infections.

Background The DeWorm3 project is an ongoing cluster-randomised trial assessing the feasibility of interrupting the transmission of soil-transmitted helminths (STH) through mass drug administration (MDA) using study sites in India, Malawi and Benin. In this article, we describe an approach which uses a combination of statistical and mathematical methods to forecast the outcome of the trial with respect to its stated goal of reducing the prevalence of infection to below 2%. Methods Our approach is first to define the local patterns of transmission within each study site, which is achieved by statistical inference of key epidemiological parameters using the baseline epidemiological measures of age-related prevalence and intensity of STH infection which have been collected by the DeWorm3 trials team. We use these inferred parameters to calibrate an individual-based stochastic simulation of the trial at the cluster and study site level, which is subsequently run to forecast the future prevalence of STH infections. The simulator takes into account both the uncertainties in parameter estimation and the variability inherent in epidemiological and demographic processes in the simulator. We interpret the forecast results from our simulation with reference to the stated goal of the DeWorm3 trial, to achieve a target of $$\le 2\%$$ ≤ 2 % prevalence at a point 24 months post-cessation of MDA. Results Simulated output predicts that the two arms will be distinguishable from each other in all three country sites at the study end point. In India and Malawi, measured prevalence in the intervention arm is below the threshold with a high probability (90% and 95%, respectively), but in Benin the heterogeneity between clusters prevents the arm prevalence from being reduced below the threshold value. At the level of individual study arms within each site, heterogeneity among clusters leads to a very low probability of achieving complete elimination in an intervention arm, yielding a post-study scenario with widespread elimination but a few ‘hot spot’ areas of persisting STH transmission. Conclusions Our results suggest that geographical heterogeneities in transmission intensity and worm aggregation have a large impact on the effect of MDA. It is important to accurately assess cluster-level, or even smaller scale, heterogeneities in factors which influence transmission and aggregation for a clearer perspective on projecting the outcomes of MDA control of STH and other neglected tropical diseases. Graphical Abstract

Global efforts to control morbidity associated with soil-transmitted helminth infections (STH) have focused largely on the targeted treatment of high-risk groups, including children and pregnant women. However, it is not clear when such programs can be discontinued and there are concerns about the sustainability of current STH control programs. The DeWorm3 project is a large multi-country community cluster randomized trial in Benin, India and Malawi designed to determine the feasibility of interrupting the transmission of STH using community-wide delivery of mass drug administration (MDA) with anthelmintics over multiple rounds. Here, we present baseline data and estimate key epidemiological parameters important in determining the likelihood of transmission interruption in the DeWorm3 trial. A baseline census was conducted in October-December 2017 in India, November-December 2017 in Malawi and in January-February 2018 in Benin. The baseline census enumerated all members of each household and collected demographic data and information on occupation, assets, and access to water, sanitation and hygiene (WASH). Each study site was divided into 40 clusters of at least 1,650 individuals per cluster. Clusters were randomized to receive twice yearly community-wide MDA with albendazole (GSK) targeting eligible individuals of all ages (20 clusters), or to receive the standard-of-care deworming program targeting children provided in each country. In each site, a randomly selected group of 150 individuals per cluster (6,000 total per site) was selected from the baseline census using stratified random sampling, and each individual provided a single stool sample for analysis of STH infection using the Kato-Katz technique. Study site, household and individual characteristics were summarized as appropriate. We estimated key epidemiological parameters including the force of infection and the degree of parasite aggregation within the population. The DeWorm3 sites range in population from 94,969 to 140,932. The population age distribution varied significantly by site, with the highest proportion of infants and young children in Malawi and the highest proportion of adults in India. The baseline age- and cluster-weighted prevalence, as measured by Kato-Katz, varied across sites and by species, Baseline hookworm prevalence in India was 21.4% (95% CI: 20.4–22.4%), while prevalence of Ascaris and Trichuris by Kato-Katz was low (0.1% and 0.3% overall). In Malawi, the overall age- and cluster-weighted STH prevalence was 7.7% (95% CI: 7.1–8.4%) predominantly driven by hookworm infections (7.4%) while Ascaris (0.1%) and Trichuris (0.3%) infections were rare. In Benin, the overall age- and cluster-weighted prevalence was significantly lower (5.6%, 95% CI: 5.1–6.2%) and Ascaris (2.0%, 95% CI: 1.6–2.3%) was more common than in other sites. Ascaris infections were more likely to be moderate- or heavy-intensity (43.7%, unweighted) compared to hookworm (5.0%). The force of infection for hookworm was highest in adults in India and Malawi but appeared relatively stable across age groups in Benin. These data demonstrate the significant variability between the sites in terms of demography, socio-economic status and environmental characteristics. In addition, the baseline prevalence and intensity data from DeWorm3 suggest that each site has unique epidemiologic characteristics that will be critical in determining correlates of achieving STH transmission interruption in the DeWorm3 trial. Trial registration: The trial was registered at ClinicalTrials.gov (NCT03014167)., Author summary Intestinal parasitic worms, soil-transmitted helminths, are among the most common infectious organisms of humans. In many low-resource settings, these infections result in considerable morbidity, including reductions in childhood growth and development, increased risk of anemia and reductions in future educational achievement and income earning potential. The current global strategy for controlling these infections is through routine deworming of school and pre-school aged children as well as pregnant women. Since many adults and non-school going children are infected with these parasites, the current strategy does not prevent the rapid reinfection of individuals despite repeated treatment. The DeWorm3 trial is a large multi-country trial being conducted in Benin, India and Malawi to test the feasibility of using mass drug administration of deworming medications to all individuals in a community to interrupt these infections in some geographic areas. Here we present baseline data from these communities and estimate the transmission potential of these infections at each of the sites.

Placental malaria has been associated with an immune tolerance phenomenon and a higher susceptibility to malaria infection during infancy. HLA-G is involved in fetal maternal immune tolerance by inhibiting maternal immunity. During infections HLA-G can be involved in immune escape of pathogens by creating a tolerogenic environment. Recent studies have shown an association between the risk of malaria and HLA-G at both genetic and protein levels. Moreover, women with placental malaria have a higher probability of giving birth to children exhibiting high sHLA-G, independently of their own level during pregnancy. Our aim was to explore the association between the level of maternal soluble HLA-G and the risk of malaria infection in their newborns. Here, 400 pregnant women and their children were actively followed-up during 24 months. The results show a significant association between the level of sHLA-G at the first antenatal visit and the time to first malaria infection during infancy adjusted to the risk of exposure to vector bites (aHR = 1.02, 95%CI [1.01–1.03], p = 0.014). The level of sHLA-G is a significant predictor of the occurrence of malaria infection during infancy consistent with the hypothesis that mother sHLA-G could be a biomarker of malaria susceptibility in children.

Background: Primary healthcare is a key element of management of childhood illness in Africa. The objectives were to identify primary care seeking determinants among infants and young children up to 18 mo in a birth cohort from Benin. Methods: From 2007 to 2009 in Benin, a birth cohort was followed until the age of 18 mo in three health centres. Multilevel Poisson regression models were fitted to identify the factors related to the monthly number of consultations. Maternal and newborn characteristics and infant general health parameters were considered. Results: A total of 566 children were followed. On average, 0.46 consultations per month per child were recorded. The number of consultations was significantly lower after the first 6 mo of life (p1000 m was associated with fewer consultations (p=0.01). Primiparity was significantly associated with higher care seeking (relative risk 1.17 [95% CI 1.05 to 1.30], p0.16). Conclusions: Development of health structures and improvement of access remain important goals for strengthening of the primary care health system. Studying factors of care seeking behaviour, like parity, can help to identify women more prone to seek care for their child during the first year of life.

The World Health Organization (WHO) estimates that 40% of children in low-income countries are anemic. Therefore, iron supplements are recommended by WHO in areas with high anemia rates. However, some studies have set into question the benefits of iron supplementation in malaria-endemic regions. In Benin, a west African country with high prevalence of anemia and malaria, no iron supplements are given systematically to infants so far despite the WHO recommendations. In this context, we wanted to investigate the effect of iron levels during the first year of life on malarial risk in Benin considering complementary risk factors. We followed 400 women and their offspring between January 2010 and June 2012 in Allada (Benin). Environmental, obstetric, and numerous clinical, maternal, and infant risk factors were considered. In multilevel models, high iron levels were significantly associated with the risk of a positive blood smear (adjusted odds ratio = 2.90, P < 0.001) and Plasmodium falciparum parasitemia (beta estimate = 0.38, P < 0.001). Infants with iron levels in the lowest quartile were less likely to have a positive blood smear (P < 0.001), and the risk increased with higher iron levels. Our results appeal for additional evaluation of the effect of different doses of iron supplements on the infant health status, including malaria incidence. Thus, the health status of infants should be compared between cohorts where iron is given either for prevention or anemia treatment, to better understand the effect of iron supplements on infant health.

Introduction: HLA-G plays a key role on immune tolerance. Pathogens can induce soluble HLA-G (sHLA-G) production to down-regulate the host immune response, creating a tolerogenic environment favorable for their dissemination. To our knowledge, no study has yet been conducted to assess the relationship between sHLA-G and geohelminth infections. Methods: The study was conducted in Allada, Southeastern Benin, from 2011 - 2014. The study population encompassed 400 pregnant women, included before the end of the 28th week of gestation and followed-up until delivery. At two antenatal care visits and at delivery, stool and blood samples were collected. Helminths were diagnosed by means of the Kato-Katz concentration technique. We used quantile regression to analyze the association between helminth infections and sHLA-G levels during pregnancy. Results: sHLA-G levels gradually increased during pregnancy and reached maximal levels at delivery. Prevalence of helminth infections was low, with a majority of hookworm infections. We found significantly more hookworm-infected women above the 80th quantile (Q80) of the distribution of the mean sHLA-G level (p < 0.03, multivariate quantile regression). Considering only women above the Q80 percentile, the mean sHLA-G level was significantly higher in hookworm-infected compared to uninfected women (p = 0.04). Conclusion: High levels of sHLA-G were associated with hookworm infection in pregnant women. This result is consistent with the potential involvement of sHLA-G in immune tolerance induced by helminths during pregnancy.

International audience; Background. Sickle cell trait (HbAS) confers partial protection against malaria by reducing the adhesion of Plasmodium falciparum-infected erythrocytes to host receptors, but little is known about its potential protection against placental malaria. Methods. Using flow cytometry, we assessed the recognition of HbAA and HbAS VAR2CSA-expressing infected erythrocytes, by plasma from 159 Beninese pregnant women with either HbAA (normal) or HbAS. Using multivariate linear models adjusted for gravidity, parasite infection at delivery, glucose-6-phosphate dehydrogenase deficiency, and α-thalassemia carriage, we observed significantly reduced cell surface antibody binding of HbAS-infected erythrocytes by plasma from HbAS compared with HbAA women (P < 10-3). Results. The difference in cell surface antibody binding was only observed when infected erythrocytes and plasma were associated according to the same hemoglobin genotype. Similar levels of VAR2CSA-specific antibody were measured by enzyme-linked immunosorbent assay in the 2 groups, suggesting that the altered interaction between VAR2CSA and HbAS women's antibodies could reflect abnormal display of VAR2CSA on HbAS erythrocytes. Conclusions. Our data stress the need for assessments of erythrocyte disorders such as the sickle cell trait in a population group when studying immunological responses to P falciparum.

BACKGROUND: Substantial evidence indicates that cytophilic IgG responses to Plasmodium falciparum merozoite antigens play a role in protection from malaria. The specific targets mediating immunity remain unclear. Evaluating antibody responses in infants naturally-exposed to malaria will allow to better understand the establishment of anti-malarial immunity and to contribute to a vaccine development by identifying the most appropriate merozoite candidate antigens.METHODS: The study was based on parasitological and clinical active follow-up of infants from birth to 18 months of age conducted in the Tori Bossito area of southern Benin. For 399 infants, plasma levels of cytophilic IgG antibodies with specificity for five asexual stage malaria vaccine candidate antigens were determined by ELISA in infants' peripheral blood at 6, 9, 12 and 15 months of age. Multivariate mixed logistic model was used to investigate the association between antibody levels and anti-malarial protection in the trimester following the IgG quantification. Moreover, the concentrations of merozoite antigen-specific IgG were compared between a group of infants apparently able to control asymptomatic malaria infection (CAIG) and a group of infants with no control of malaria infection (Control group (NCIG)). Protective effect of antibodies was also assessed after 15 months of malaria exposure with a Cox regression model adjusted on environmental risk.RESULTS: Cytophilic IgG responses to AMA1, MSP1, MSP2-3D7, MSP2-FC27, MSP3 and GLURP R2 were associated with increasing malarial infection risk in univariate analysis. The multivariate mixed model showed that IgG1 and IgG3 to AMA1 were associated with an increased risk of malarial infection. However infants from CAIG (n = 53) had significantly higher AMA1-, MSP2-FC27-, MSP3-specific IgG1 and AMA1-, MSP1-, MSP2-FC27-, MSP3 and GLURP-R2-specific IgG3 than those from NCIG (n = 183). The latter IgG responses were not associated with protection against clinical malaria in the whole cohort when protective effect is assessed after 15 months of malaria exposition.CONCLUSION: In this cohort, merozoite antigen-specific cytophilic IgG levels represent a marker of malaria exposure in infants from 6 to 18 months of age. However, infants with resolution of asymptomatic infection (CAIG) seem to have acquired naturally immunity against P. falciparum. This observation is encouraging in the context of the development of multitarget P. falciparum vaccines.

Despite the clinically proven advantages of intermittent preventive treatment of malaria in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP), utilisation has been low in many African countries. To increase uptake and achieve the desired effect, the World Health Organization revised the policy to a monthly administration. Assessing the coverage and impact of the revised policy on pregnancy and neonatal outcomes is, therefore, a necessity. A 2-parallel cross-sectional hospital-based study was carried out among pregnant women attending first antenatal care (ANC) and delivery. Maternal and cord blood samples were assayed for malaria parasites by quantitative PCR targeting both the 18S rDNA and the acidic terminal segment of Plasmodium falciparum var genes, and plasma SP levels were measured by liquid chromatography coupled to tandem mass spectrometry. Parasite prevalence was similar between the two study sites but decreased significantly between the first ANC (9% or 43%) and delivery (4% or 11%) based on the qPCR target. At delivery, 64.5% of women received ≥3 IPTp-SP dose, 15.5% received 2 doses and 6% had 1 dose. Taking ≥3 IPTp-SP doses was associated with an average birth weight increase of more than 0.165 kg. IPTp-SP uptake was associated with plasma SP level at delivery (OR = 32.3, p ≤ 0.005, 95% CI (13.3;78.4) for those that reported ≥3 IPTp-SP doses) while the same trend of improved birth weight was observed with high plasma SP levels. The new IPTp policy is well implemented and well utilised by women in the sites considered in this study and translates to the improved birth weight observed. This study confirms the interest and the clinical benefit expected from this policy change.

IntroductionNeonatal sepsis outreaches all causes of neonatal mortality worldwide and remains a major societal burden in low and middle income countries. In addition to limited resources, endemic morbidities, such as malaria and prematurity, predispose neonates and infants to invasive infection by altering neonatal immune response to pathogens. Nevertheless, thoughtful epidemiological, diagnostic and immunological evaluation of neonatal sepsis and the impact of gestational malaria have never been performed.Methods and analysisA prospective longitudinal multicentre follow-up of 580 infants from birth to 3 months of age in urban and suburban Benin will be performed. At delivery, and every other week, all children will be examined and clinically evaluated for occurrence of sepsis. At delivery, cord blood systematic analysis of selected plasma and transcriptomic biomarkers (procalcitonin, interleukin (IL)-6, IL-10, IP10, CD74 and CX3CR1) associated with sepsis pathophysiology will be evaluated in all live births as well as during the follow-up, and when sepsis will be suspected. In addition, whole blood response to selected innate stimuli and extensive peripheral blood mononuclear cells phenotypic characterisation will be performed. Reference intervals specific to sub-Saharan neonates will be determined from this cohort and biomarkers performances for neonatal sepsis diagnosis and prognosis tested.Ethics and disseminationEthical approval has been obtained from the Comité d’Ethique de la Recherche – Institut des Sciences Biomédicales Appliquées (CER-ISBA 85 - 5 April 2016, extended on 3 February 2017). Results will be disseminated through international presentations at scientific meetings and publications in peer-reviewed journals.Trial registration numberClinicalTrials.gov registration number: NCT03780712.

Background In sub-Saharan Africa, malaria in the first half of pregnancy is harmful for both the mother and her fetus. However, malaria in the first trimester of pregnancy, when women are usually not protected against malaria, has been little investigated. For the first time, we assessed the effects of malaria in the first trimester on maternal and birth outcomes using a preconceptional study design. Methods From June 2014 to March 2017, 1214 women of reproductive age were recruited and followed monthly until 411 became pregnant. The pregnant women were then followed from 5–6 weeks of gestation until delivery. Path analysis was used to assess the direct effect (ie, not mediated by malaria in the second or third trimester) of malaria in the first trimester on maternal anemia and poor birth outcomes. The cumulative effect of infections during pregnancy on the same outcomes was also evaluated. Results The prevalence of malaria infections in the first trimester was 21.8%. Malaria in the first trimester was significantly associated with maternal anemia in the third trimester (adjusted odds ratio 2.25, 95% confidence interval 1.11–4.55). While we did not find evidence of any direct effect of first trimester malaria infections on birth outcomes, their association with infections later in pregnancy tended to increase the risk of low birth weights. Conclusions Malaria infections in the first trimester were highly prevalent and have deleterious effects on maternal anemia. They highlight the need for additional preventive measures, starting in early pregnancy or even before conception.

Background. According to the Developmental Origins of Health and Diseases paradigm, the fetal period is highly vulnerable and may have profound effects on later health. Few studies assessed the effect of small-for-gestational age (SGA), a proxy for fetal growth impairment, on risk of malaria during infancy in Africa. Methods. We used data from a cohort of 398 mother-child pairs, followed from early pregnancy to age 1 year in Benin. Malaria was actively and passively screened using thick blood smear. We assessed the effect of SGA on risk of malaria infection and clinical malaria from birth to 12 months, after stratifying on the infant's age using a logistic mixed regression model. Results. After adjustment for potential confounding factors and infant's exposure to mosquitoes, SGA was associated with a 2-times higher risk of malaria infection (adjusted odds ratio [aOR] = 2.16; 95% confidence interval [CI], 1.04-4.51; P = .039) and clinical malaria (aOR = 2.33; 95% CI, 1.09-4.98; P = .030) after age 6 months. Conclusion. Results suggest higher risk of malaria during the second semester of life in SGA infants, and argue for better follow-up of these infants after birth, as currently for preterm babies.

Timely identification and treatment of malaria transmission "hot spots" is essential to achieve malaria elimination. Here we investigate the relevance of using an Anopheles salivary biomarker to estimate Plasmodium falciparum malaria exposure risk along the Thailand-Myanmar border to guide malaria control. Between May 2013 and December 2014, > 9,000 blood samples collected in a cluster randomized control trial were screened with serological assays to measure the antibody responses to Anopheles salivary antigen (gSG6-P1) and P. falciparum malaria antigens (circumsporozoite protein, merozoite surface protein 119 [MSP-119]). Plasmodium falciparum infections were monitored through passive and active case detection. Seroprevalence to gSG6-P1, MSP-119, and CSP were 71.8% (95% Confidence interval [CI]: 70.9, 72.7), 68.6% (95% CI: 67.7, 69.5), and 8.6% (95% CI: 8.0, 9.2), respectively. Multivariate analysis showed that individuals with the highest Ab response to gSG6-P1 had six times the odds of being positive to CSP antigens (P < 0.001) and two times the odds of P. falciparum infection compared with low gSG6-P1 responders (P = 0.004). Spatial scan statistics revealed the presence of clusters of gSG6-P1 that partially overlapped P. falciparum infections. The gSG6-P1 salivary biomarker represents a good proxy for estimating P. falciparum malaria risk and could serve to implement hot spot-targeted vector control interventions to achieve malaria elimination.

Background Malaria in pregnancy is prevalent in Sub-Saharan Africa. The first trimester of pregnancy is a critical period and the best preventive measure is Long Lasting Insecticidal Nets (LLIN). Unfortunately, few studies have been conducted which focuses on the usage and efficacy of LLIN on malaria prevention during the first trimester. Methods We assessed the use and effectiveness of LLIN in early pregnancy in Benin and its impact on malaria infection risk. We followed-up a cohort of 240 pregnant women from pre-conception to the end of the first trimester of pregnancy in Southern Benin. Parasitological, maternal and LLIN data were actively collected before, at the beginning and end of the first trimester of pregnancy. A Cox regression model was used to determine the relationship between the time to onset of the first malaria infection and the use, physical integrity, and bio-efficacy of the LLIN, adjusted for relevant covariables. Results The good use, good physical integrity and biological efficacy of LLIN were associated with a decreased risk of occurrence of the first malaria infection in early pregnancy (HRa = 0.38; (0.18–0.80); p

We aimed to determine if children born to mothers with placental malaria are more susceptible to malaria and remain at higher risk between birth and 18 months. From a public health point of view, protecting children born to infected placenta remains a priority.Children born to mothers with placental malaria (PM) have been described as more susceptible to the occurrence of a first malaria infection. However, whether or not these children remain more at risk during infancy has never been explored. We aimed to determine if children born to mothers with PM are more susceptible to malaria and remain at higher risk between birth and 18 months. Five hundred fifty children were followed up weekly with control of temperature and, if > 37.5A degrees C, both a rapid diagnostic test for malaria and a thick blood smear were performed. Taking into account environmental risk of infection, the relationship between occurrences of malaria attacks from birth to 18 months was modeled using Cox models for recurrent events. PM is not associated with an overall susceptibility to malaria but only with the delay of occurrence of the first malaria attack. Children born from mothers with PM tend to have an increased risk for the first malaria attack (hazard ratio [HR] = 1.33; P = .048) but not for subsequent ones (HR = 0.9; P = .46). Children who experienced 1 malaria attack were strongly at risk to develop subsequent infections independent of placental infection and environmental exposure. These results are consistent with the existence of an individual susceptibility to malaria unrelated to PM. From a public health point of view, protecting children born to infected placenta remains a priority, but seems insufficient to account for other frail children for whom a biomarker of frailty needs to be found.

Background. There is a lack of data on the burden of malaria in the first trimester of pregnancy in Africa, mainly because pregnant women generally attend the maternity clinic late. Bed nets are rarely provided to women before the second trimester of pregnancy and intermittent preventive treatment with sulfadoxine-pyrimethamine is not recommended before the second trimester, leaving women insufficiently or not protected in early pregnancy.& para;& para;Methods. To assess the burden of first trimester malaria, 387 women were followed up monthly from preconception to delivery. They were screened for malaria monthly from early pregnancy until delivery. A logistic multilevel model was used to assess maternal factors associated with malaria during the first trimester.& para;& para;Results. The proportion of women with at least 1 microscopic malaria infection during the first trimester of pregnancy was 20.8%. Women infected with malaria preconception were more likely to be infected during the first trimester (adjusted odds ratio: 2.68; 95% confidence interval, 1.24-5.78). Early gestational age was also positively correlated with malaria infection.& para;& para;Conclusions. Using a preconceptional study design, we showed that malaria was highly prevalent in early pregnancy. This calls for the assessment of new strategies that could protect women as soon as the first trimester.

International audience; Recent studies have highlighted the importance of local environmental factors to determine the fine-scale heterogeneity of malaria transmission and exposure to the vector. In this work, we compare a classical GLM model with backward selection with different versions of an automatic LASSO-based algorithm with 2-level cross-validation aiming to build a predic-tive model of the space and time dependent individual exposure to the malaria vector, using entomological and environmental data from a cohort study in Benin. Although the GLM can outperform the LASSO model with appropriate engineering, the best model in terms of pre-dictive power was found to be the LASSO-based model. Our approach can be adapted to different topics and may therefore be helpful to address prediction issues in other health sciences domains.