Efficient transplacental transfer of SARS-CoV-2 antibodies between naturally exposed mothers and infants in Accra, Ghana.

We aimed to determine SARS-CoV-2 antibody seropositivity among pregnant women and the transplacental transfer efficiency of SARS-CoV-2-specific antibodies relative to malaria antibodies among SARS-CoV-2 seropositive mother-cord pairs. This cross-sectional study was conducted in Accra, Ghana, from March to May 2022. Antigen- specific IgG antibodies against SARS-CoV-2 (nucleoprotein and spike-receptor binding domain) and malarial antigens (circumsporozoite protein and merozoite surface protein 3) in maternal and cord plasma were measured by ELISA. Plasma from both vaccinated and unvaccinated pregnant women were tested for neutralizing antibodies using commercial kit. Of the unvaccinated pregnant women tested, 58.12% at antenatal clinics and 55.56% at the delivery wards were seropositive for both SARS-CoV-2 nucleoprotein and RBD antibodies. Anti-SARS-CoV-2 antibodies in cord samples correlated with maternal antibody levels (N antigen rs = 0.7155, p < 0.001; RBD rs = 0.8693, p < 0.001). Transplacental transfer of SARS-CoV-2 nucleoprotein antibodies was comparable to circumsporozoite protein antibodies (p = 0.9999) but both were higher than transfer rates of merozoite surface protein 3 antibodies (p < 0.001). SARS-CoV-2 IgG seropositivity among pregnant women in Accra is high with a boost of SARS-CoV-2 RBD-specific IgG in vaccinated women. Transplacental transfer of anti-SARS-CoV-2 and malarial antibodies was efficient, supporting vaccination of mothers as a strategy to protect infants against SARS-CoV-2.

Antibody response to malaria vaccine candidates in pregnant women with Plasmodium falciparum and Schistosoma haematobium infections.

Malaria in pregnancy has severe consequences for the mother and foetus. Antibody response to specific malaria vaccine candidates (MVC) has been associated with a decreased risk of clinical malaria and its outcomes. We studied Plasmodium falciparum (Pf) and Schistosoma haematobium (Sh) infections and factors that could influence antibody responses to MVC in pregnant women. A total of 337 pregnant women receiving antenatal care (ANC) and 139 for delivery participated in this study. Pf infection was detected by qPCR and Sh infection using urine filtration method. Antibody levels against CSP, AMA-1, GLURP-R0, VAR2CSA and Pfs48/45 MVC were quantified by ELISA. Multivariable linear regression models identified factors associated with the modulation of antibody responses. The prevalence of Pf and Sh infections was 27% and 4% at ANC and 7% and 4% at delivery. Pf infection, residing in Adidome and multigravidae were positively associated with specific IgG response to CSP, AMA-1, GLURP-R0 and VAR2CSA. ITN use and IPTp were negatively associated with specific IgG response to GLURP-R0 and Pfs48/45. There was no association between Sh infection and antibody response to MVC at ANC or delivery. Pf infections in pregnant women were positively associated with antibody response to CSP, GLURP-R0 and AMA-1. Antibody response to GLURP-R0 and Pfs48/45 was low for IPTp and ITN users. This could indicate a lower exposure to Pf infection and low malaria prevalence observed at delivery.

Malaria, Urogenital Schistosomiasis, and Anaemia in Pregnant Ghanaian Women.

Background: Anaemia is common in sub-Saharan Africa, and parasitic infections could worsen its burden during pregnancy. Moreover, women become susceptible to malaria during pregnancy. We investigated Plasmodium falciparum (P. falciparum) and Schistosoma haematobium (S. haematobium) infections and determined their association with anaemia during pregnancy. Methods: A cross-sectional study involving 707 pregnant women attending antenatal care visits (ANC) and 446 at delivery was conducted in Battor and Adidome hospitals. Pregnant women were screened by microscopy and qPCR for P. falciparum and S. haematobium infections. Haemoglobin (Hb) levels were determined, and most participants received intermittent preventive treatment during pregnancy (IPTp) during ANC till delivery. Regression analyses were performed for associations between parasite infection and anaemia. Results: P. falciparum microscopy prevalence at ANC and delivery was 8% and 2%, respectively, and by PCR 24% at ANC and 12% at delivery. Anaemia prevalence at ANC was 52% and 49% at delivery. There was an increased risk of anaemia with P. falciparum infection (aOR = 1.92; p = 0.04). IPTp (p = 0.003) and age (p = 0.004) were associated with increased Hb levels at delivery. S. haematobium prevalence by microscopy was 4% at ANC and 2% at delivery. No significant correlation between S. haematobium and Hb levels was observed (coef. = -0.62 g/dl; p = 0.07). Conclusion: High anaemia prevalence was observed during pregnancy, and P. falciparum infection was associated with anaemia at ANC. Low S. haematobium prevalence could be attributed to previous praziquantel treatment during mass drug administration. Routine diagnosis and treatment of S. haematobium infections in endemic areas could be initiated to reduce schistosomiasis during pregnancy.

Combined polymorphisms involving the IgG heavy chain and Fc gamma receptors among Fulani and non-Fulani in Benin: implications for the natural protection of young Fulani against Plasmodium falciparum malaria infections.

A decreased susceptibility of Fulani populations to malaria infections has been shown in Africa. A previous longitudinal cohort study conducted in the Atacora region of northern Benin showed a high merozoite-phagocytosis capacity in young Fulani. Here, we explored the combined polymorphisms in the constant region of the IgG3 heavy chain (presence/absence of the G3m6 allotype) and in Fc gamma receptors (FcγRs) as potentially involved in the natural protection against malaria of young Fulani in Benin. An active malaria follow-up was conducted among individuals from Fulani, Bariba, Otamari and Gando ethnic groups living in sympatry in Atacora, over the full malaria transmission season. FcγRIIA 131R/H (rs1801274), FcγRIIC C/T (rs3933769) and FcγRIIIA 176F/V (rs396991) were determined using the TaqMan method; FcγRIIIB NA1/NA2 was assessed by polymerase chain reaction (PCR) using allele-specific primers and G3m6 using allotype by PCR-RFLP. Individual carriage of G3m6 (+) was associated with an increased risk of Pf malaria infection (logistic multivariate regression model (lmrm), OR = 2.25, 95% CI = 1.06;4.74, P = 0.034). Combined haplotype G3m6 (+) - FcγRIIA 131H - FcγRIIC T - FcγRIIIA 176F - FcγRIIIB NA2 was also associated with an increased risk of Pf malaria infection (lmrm, OR = 13.01, 95% CI = 1.69;99.76, P = 0.014). G3m6 (-), FcγRIIA 131R and FcγRIIIB NA1 were more prevalent in young Fulani (P = 0.002, P < 0.001 and P = 0.049, respectively), while no Fulani presented the combined G3m6 (+) - FcγRIIA 131H - FcγRIIC T - FcγRIIIA 176F - FcγRIIIB NA2 haplotype that was carried by a majority of infected children. Our results highlight the combined factors G3m6 - FcγR as potentially involved in the merozoite-phagocytosis capacity and in the natural protection of young Fulani individuals against P. falciparum malaria in Benin.

Evidence for Epistatic Interaction between HLA-G and LILRB1 in the Pathogenesis of Nonsegmental Vitiligo.

Vitiligo is the most frequent cause of depigmentation worldwide. Genetic association studies have discovered about 50 loci associated with disease, many with immunological functions. Among them is HLA-G, which modulates immunity by interacting with specific inhibitory receptors, mainly LILRB1 and LILRB2. Here we investigated the LILRB1 and LILRB2 association with vitiligo risk and evaluated the possible role of interactions between HLA-G and its receptors in this pathogenesis. We tested the association of the polymorphisms of HLA-G, LILRB1, and LILRB2 with vitiligo using logistic regression along with adjustment by ancestry. Further, methods based on the multifactor dimensionality reduction (MDR) approach (MDR v.3.0.2, GMDR v.0.9, and MB-MDR) were used to detect potential epistatic interactions between polymorphisms from the three genes. An interaction involving rs9380142 and rs2114511 polymorphisms was identified by all methods used. The polymorphism rs9380142 is an HLA-G 3'UTR variant (+3187) with a well-established role in mRNA stability. The polymorphism rs2114511 is located in the exonic region of LILRB1. Although no association involving this SNP has been reported, ChIP-Seq experiments have identified this position as an EBF1 binding site. These results highlight the role of an epistatic interaction between HLA-G and LILRB1 in vitiligo pathogenesis.

Susceptibility to malaria in fulani, Bariba, Otamari and gando individuals living in sympatry in Benin: Role of opsonizing antibodies to Plasmodium falciparum merozoites.

Objectives: Fulani in Africa are known to be less susceptible to Plasmodium falciparum (Pf) malaria. This study explored a potential involvement of antibody-mediated merozoite phagocytosis mechanism in this natural protection against malaria. Methods: Before the start of the malaria transmission season (MTS) in Benin, the functionality of antibodies against Pf merozoites was determined by the opsonic phagocytosis (OP) assay in plasma samples from Fulani, Bariba, Otamari and Gando groups. These individuals were actively followed-up for malaria detection from the beginning to the end of MTS. Anti-GLURP Immunoglobulin G antibody quantification, malaria Rapid Diagnostic Test (RDT) and spleen palpation were performed before and after MTS. Results: In Bariba, Otamari and Gando, but not in Fulani, plasma from adults promoted higher levels of OP than the children (P = 0.003; P = 0.012; P = 0.031 and P = 0.122). A high proportion of Fulani children had higher OP and anti-GLURP (P < 0.0001) antibody levels as compared to non-Fulani children; whereas this was not observed for Fulani adults (P = 0.223). High OP levels before MTS were significantly related to negative RDT after MTS (P = 0.011). Conclusion: Our results highlight the ability of opsonizing antibodies to potentially enhance natural protection of young Fulani individuals against Pf malaria in Benin.

Population-based sero-epidemiological investigation of the dynamics of SARS-CoV-2 infections in the Greater Accra Region of Ghana.

The coronavirus disease 2019 (COVID-19) pandemic devastated countries worldwide, and resulted in a global shutdown. Not all infections are symptomatic and hence the extent of SARS-CoV-2 infection in the community is unknown. The paper presents the dynamics of the SARS-CoV-2 epidemic in the Greater Accra Metropolis, describing the evolution of seroprevalence through time and by age group. Three repeated independent population-based surveys at 6-week intervals were conducted in from November 2020 to July 2021. The global and by age-groups weighted seroprevalences were estimated and the risk factors for SARS-CoV-2 antibody seropositivity were assessed using logistic regression. The overall age-standardized SARS-CoV-2 antibody seroprevalence for both spike and nucleocapsid increased from 13.8% (95% CI 11.9, 16.1) in November 2020 to 39.6% (95% CI 34.8, 44.6) in July 2021. After controlling for gender, marital status, education level, and occupation, the older age group over 40 years had a higher odds of seropositivity than the younger age group (OR 3.0 [95% CI 1.1-8.5]) in the final survey. Pupils or students had 3.3-fold increased odds of seropositivity (OR 3.2 [95% CI 1.1-8.5]) compared to the unemployed. This study reinforces that, SARS-CoV-2 infections have been significantly higher than reported.

Fc Gamma Receptor IIIB NA1/NA2/SH Polymorphisms Are Associated with Malaria Susceptibility and Antibody Levels to P. falciparum Merozoite Antigens in Beninese Children.

This paper aimed to investigate the influence of polymorphisms in the FCGR2A gene encoding R131H FcgRIIA variants and in the FCGR3B gene (108G > C, 114C > T, 194 A > G, 233C > A, 244 G > A and 316G > A) encoding FcgRIIIB-NA1, -NA2 and -SH variants on malaria susceptibility and antibody responses against P. falciparum merozoite antigens in Beninese children. An active malaria follow-up was conducted in infants from birth to 24 months of age in Allada, Benin. FCGR3B exon 3 was sequenced and FCGR2A exon 4 was genotyped. Antibodies directed to GLURP and MSP3 were quantified by ELISA. Association studies were performed using mixed-effect models. Individual carriage of FCGR3B 194 AA genotype was associated with a high number of malaria infections and a low level of IgG1 against MSP3 and GLURP-R0. High parasitemia and increased malaria infections were observed in infants carrying the FCGR3B*05 108C-114T-194A-233C-244A-316A haplotype. A reduced risk of malaria infections and low parasitemia were related to the carriages of the FCGR3B 108C-114T-194G-233C-244G-316A (FCGR3B*06), FCGR3B 108C−114T−194G−233A−244A−316A (FCGR3B*03 encoding for FcgRIIIB-SH) haplotypes and FCGR3B 297 TT genotype. Our results highlight the impact of FCGR3B polymorphisms on the individual susceptibility to malaria and antibody responses against MSP3 and GLURP in Beninese children.

Naturally acquired antibodies from Beninese infants promote Plasmodium falciparum merozoite-phagocytosis by human blood leukocytes: implications for control of asymptomatic malaria infections.

BACKGROUND: Immunoglobulin G (IgG) antibodies are thought to play important roles in the protection against Plasmodium falciparum (P. falciparum) malaria. A longitudinal cohort study performed in the Southern part of Benin, identified a group of infants who were able to control asymptomatic malaria infections (CAIG). METHODS: IgG antibodies against distinct merozoite antigens were quantified in plasma from Beninese infants. Functionality of these antibodies was assessed by the merozoite-phagocytosis assay using THP-1 cells and primary neutrophils as effector cells. Gm allotypes were determined by a serological method of haemagglutination inhibition. RESULTS: Purified IgG from infants in CAIG promoted higher levels of merozoite-phagocytosis than did IgG from children who were unable to control asymptomatic infections (Ologit multivariate regression model, Coef. = 0.06, 95% CI 0.02;0.10, P = 0.002). High level of merozoite-phagocytosis activity was significantly associated with high levels of IgG against AMA1 (Coef. = 1.76, 95% CI 0.39;3.14, P = 0.012) and GLURP-R2 (Coef. = 12.24, 95% CI 1.35;23.12, P = 0.028). Moreover, infants of the G3m5,6,10,11,13,14,24 phenotype showed higher merozoite-phagocytosis activity (Generalized linear model multivariate regression, Coef. = 7.46, 95% CI 0.31;14.61, P = 0.041) than those presenting other G3m phenotypes. CONCLUSION: The results of the present study confirm the importance of antibodies to merozoite surface antigens in the control of asymptomatic malaria infection in Beninese infants. The study also demonstrated that G3m phenotypes impact the functional activity of IgG. This last point could have a considerable impact in the research of candidate vaccines against malaria parasites or other pathogens.

Placental Malaria is Associated with Higher LILRB2 Expression in Monocyte Subsets and Lower Anti-Malarial IgG Antibodies During Infancy.

Background: Placental 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. Method: Infants of women 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. Findings: Infants born to women with PM had a higher risk of developing symptomatic malaria than those born to women 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 women with PM had lower levels of cytophilic IgG and higher levels of IL-10 during active infection. Interpretation: Modulation of IgG and IL-10 levels could impair monocyte functions (opsonisation/phagocytosis) in infants born to women with PM, 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.

Splenic clearance of rigid erythrocytes as an inherited mechanism for splenomegaly and natural resistance to malaria.

BACKGROUND: In malaria-endemic areas, subjects from specific groups like Fulani have a peculiar protection against malaria, with high levels of IgM but also frequent anaemia and splenomegaly. The mechanisms underlying this phenotype remain elusive. METHODS: In a cohort study set up in Benin, West Africa, after a careful evaluation of malaria-related phenotypes, we measured the deformability of circulating erythrocytes in genetically distinct groups (including Fulani) living in sympatry, using ektacytometry and microsphiltration, a mimic of how the spleen clears rigid erythrocytes. Heritability of erythrocytes deformability was calculated, followed by a genome-wide association study (GWAS) of the same phenotype. FINDINGS: Compared to non-Fulani, Fulani displayed a higher deformability of circulating erythrocytes, pointing to an enhanced clearance of rigid erythrocytes by the spleen. This phenotype was observed in individuals displaying markers of Plasmodium falciparum infection. The heritability of this new trait was high, with a strong multigenic component. Five of the top 10 genes selected by a population structure-adjusted GWAS, expressed in the spleen, are potentially involved in splenic clearance of erythrocytes (CHERP, MB, PALLD, SPARC, PDE10A), through control of vascular tone, collagen synthesis and macrophage activity. INTERPRETATION: In specific ethnic groups, genetically-controlled processes likely enhance the innate retention of infected and uninfected erythrocytes in the spleen, explaining splenomegaly, anaemia, cryptic intrasplenic parasite loads, hyper-IgM, and partial protection against malaria. Beyond malaria-related phenotypes, inherited splenic hyper-filtration of erythrocytes may impact the pathogenesis of other hematologic diseases. FUNDING: ANR, National Geographic Society, IMEA, IRD, and Région Ile-de-France.

Genetic diversity of the LILRB1 and LILRB2 coding regions in an admixed Brazilian population sample.

Leukocyte immunoglobulin (Ig)-like receptors (LILR) LILRB1 and LILRB2 may play a pivotal role in maintaining self-tolerance and modulating the immune response through interaction with classical and nonclassical HLA molecules. Although both diversity and natural selection patterns over HLA genes have been extensively evaluated, little information is available concerning the genetic diversity and selection signatures on the LILRB1/2 regions. Therefore, we identified the LILRB1/2 genetic diversity using next-generation sequencing in a population sample from São Paulo State, Brazil. We identified 58 LILRB1 Single Nucleotide Variants (SNVs), which gave rise to 13 haplotypes, and 41 LILRB2 SNVs arranged into 11 haplotypes. Although we may not exclude as a possible effect of population structure, we found evidence of either positive or purifying selection on LILRB1/2 coding regions. Some residues in both proteins showed to be under the effect of positive selection, suggesting that amino acid replacements in these proteins resulted in beneficial functional changes. Finally, we have revealed that allelic variation (six and five amino acid exchanges in LILRB1 and LILRB2, respectively) affects the structure and/or stability of both molecules. Nonetheless, LILRB2 has shown higher average stability, with no D1/D2 residue affecting protein structure. Overall, our findings demonstrate that LILRB1 and LILRB2 are as polymorphic as HLA class Ib genes and provide strong evidence supporting the directional selection regime hypothesis.

Plasmodium falciparum coinfection is associated with improved IgE and IgG3 response against hookworm antigens.

Background: Plasmodium falciparum and Hookworm infections are prevalent in West Africa and they cause iron deficiency anemia and protein malnutrition in Children. Immune response of these parasites interact and their interactions could have repercussions on vaccine development and efficacy. The current goal of hookworm eradication lies on vaccination. We evaluated the effect of P. falciparum coinfection and albendazole treatment on naturally acquired antibody profile against hookworm L3 stage larvae antigen. Methods: In a longitudinal study, 40 individuals infected with Necator americanus only, 63 participants infected with N. americanus and P. falciparum, and 36 nonendemic controls (NECs) were recruited. The study was done in the Kintampo North Metropolis of Ghana. Stool and blood samples were taken for laboratory analyses. Serum samples were obtained before hookworm treatment and 3 weeks after treatment. Results: The malaria-hookworm (N. americanus and P. falciparum) coinfected subjects had significantly higher levels of IgE (ß = 0.30, 95% CI = [0.12, 0.48], p = 0.023) and IgG3 (ß = 0.15, 95% CI = [0.02, 0.52], p = 0.004) compared to those infected with hookworm only (N. americanus). The N. americanus groups had significantly higher levels of IgG3 (ß = 0.39, 95% CI = [0.14-0.62], p = 0.002) compared to the control group. Similarly, N. americanus and P. falciparum coinfected participants had significantly higher levels of IgE (ß = 0.35, 95% CI = [0.70-0.39], p = 0.002) and IgG3 (ß = 0.54, 95% CI = [0.22-0.76], p = 0.002). Moreover, albendazole treatment led to a significant reduction in IgE, IgA, IgM, and IgG3 antibodies against hookworm L3 stage larvae (p < 0.05). Conclusion: P. falciparum is associated with improved IgE and IgG response against hookworm L3 stage larvae. Treatment with single dose of albendazole led to reduction in naturally acquired immune response against hookworm infection. Thus, P. falciparum infection may have a boosting effect on hookworm vaccine effectiveness.

Intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine and parasite resistance: cross-sectional surveys from antenatal care visit and delivery in rural Ghana.

BACKGROUND: Despite decades of prevention efforts, the burden of malaria in pregnancy (MiP) remains a great public health concern. Sulfadoxine-pyrimethamine (SP), used as intermittent preventive treatment in pregnancy (IPTp-SP) is an important component of the malaria prevention strategy implemented in Africa. However, IPTp-SP is under constant threat from parasite resistance, thus requires regular evaluation to inform decision-making bodies. METHODS: In two malaria endemic communities in the Volta region (Adidome and Battor), a cross-sectional hospital-based study was conducted in pregnant women recruited at their first antenatal care (ANC) visit and at delivery. Basic clinical and demographic information were documented and their antenatal records were reviewed to confirm IPTp-SP adherence. Peripheral and placental blood were assayed for the presence of Plasmodium falciparum parasites by quantitative polymerase chain reaction (qPCR). One hundred and twenty (120) positive samples were genotyped for mutations associated with SP resistance. RESULTS: At first ANC visit, P. falciparum prevalence was 28.8% in Adidome and 18.2% in Battor. At delivery, this decreased to 14.2% and 8.2%, respectively. At delivery, 66.2% of the women had taken at least the recommended 3 or more doses of IPTp-SP and there was no difference between the two communities. Taking at least 3 IPTp-SP doses was associated with an average birth weight increase of more than 360 g at both study sites compared to women who did not take treatment (p = 0.003). The Pfdhfr/Pfdhps quintuple mutant IRNI-A/FGKAA was the most prevalent (46.7%) haplotype found and the nonsynonymous Pfdhps mutation at codon A581G was higher at delivery among post-SP treatment isolates (40.6%) compared to those of first ANC (10.22%). There was also an increase in the A581G mutation in isolates from women who took 3 or more IPTp-SP. CONCLUSIONS: This study confirms a positive impact following the implementation of the new IPTp-SP policy in Ghana in increasing the birth weight of newborns. However, the selection pressure exerted by the recommended 3 or more doses of IPTp-SP results in the emergence of parasites carrying the non-synonymous mutation on codon A581G. This constant selective pressure calls into question the time remaining for the clinical utility of IPTp-SP treatment during pregnancy in Africa.

The Impact of Maternal Depression and Parent-Child Interactions on Risk of Parasitic Infections in Early Childhood: A Prospective Cohort in Benin.

OBJECTIVES: Maternal depression occurs in 13-20% of women from low-income countries, which is associated with negative child health outcomes, including diarrheal disease. However, few studies have investigated its impact on child risk of infectious disease. We studied the impacts of maternal depressive symptoms and parent-child interactions, independently, on the risk of Plasmodium falciparum malaria and soil-transmitted helminth infection in Beninese children. METHODS: Our population included mothers and children enrolled in a clinical trial during pregnancy (MiPPAD) in Benin. The Edinburgh Postnatal Depression Scale (EPDS) assessed maternal depressive symptoms and the home observation measurement of the environment (HOME) assessed parent-child interactions. Blood and stool sample analyses diagnosed child malaria and helminth infection at 12, 18, and 24 months. Negative binomial and Poisson regression models with robust variance tested associations. RESULTS: Of the 302 mother-child pairs, 39 (12.9%) mothers had depressive symptoms. Median number of malaria episodes per child was 3 (0-14) and 29.1% children had at least one helminth infection. Higher EPDS scores were associated with lower HOME scores; relative risk (RR) 0.97 (95% confidence interval (CI) 0.95, 0.99), particularly with lower acceptance, involvement, and variety subscales; RR 0.92 (95% CI 0.85, 0.99), RR 0.82 (95% CI 0.77, 0.88), RR 0.93 (95% CI 0.88, 0.99), respectively. However, neither exposure was associated with risk of parasitic infection in children. CONCLUSIONS FOR PRACTICE: Maternal depressive symptoms are associated with poor parent-child interactions, particularly acceptance of behavior, involvement with children, and variety of interactions, but these exposures do not independently impact risk of parasitic infection in children.

Soil-transmitted helminth infection in pregnancy and long-term child neurocognitive and behavioral development: A prospective mother-child cohort in Benin.

BACKGROUND: An estimated 30% of women in Sub-Saharan Africa suffer from soil-transmitted helminth infection during pregnancy (SHIP), which has been shown to increase risk of pre-term birth, low birth weight, and maternal anemia. A previous study in Benin found that SHIP was associated with impaired cognitive and gross motor development scores in 635 one-year-old children. The objective of the present study was to follow children prospectively to investigate whether the association between SHIP and child neurocognitive and behavioral development persisted at age six. PRINCIPAL FINDINGS: Our prospective child cohort included 487 live-born singletons of pregnant women enrolled in the Malaria in Pregnancy Preventive Alternative Drugs clinical trial in Allada, Benin. SHIP was assessed at three antenatal visits (ANVs) through collection and testing of stool samples. Neurocognitive and behavioral development was assessed in six-year-old children by trained investigators using the Kaufman Assessment Battery for Children 2nd edition and the parent-reported Strengths and Difficulties Questionnaire (SDQ). Multiple linear regression models generated coefficients and 95% confidence intervals and potential mediating factors were tested. Prevalence of SHIP was 13% at the 1st ANV, 9% at the 2nd ANV, and 1% at delivery. SHIP was not associated with low neurocognitive scores in children at six years. Higher SDQ internalizing scores, indicating increased emotional impairments in children, were associated with helminth infection at the 2nd ANV/delivery 1.07 (95% CI 0.15, 2.00) and at least once during pregnancy 0.79 (95% CI 0.12, 1.46) in adjusted models. Mediation analysis did not reveal significant indirect effects of several mediators on this association. CONCLUSIONS: Our study shows that while SHIP is not associated with impaired long-term neurocognitive development, infections may have significant negative impacts on emotional development in six-year-old children. SHIP remains a critical public health issue, and adequate prevention and treatment protocols should be enforced in low- and middle-income countries.

Human leukocyte antigen (HLA)-F and -G gene polymorphisms and haplotypes are associated with malaria susceptibility in the Beninese Toffin children.

BACKGROUND: Little attention has been devoted to the role of the immunoregulatory HLA-E/-F/-G genes in malaria. We evaluated the entire HLA-E/-F/-G variability in Beninese children highly exposed to Plasmodium falciparum (P.f.) malaria. METHODS: 154 unrelated children were followed-up for six months and evaluated for the presence and number of malaria episodes. HLA-E/-F/-G genes were genotyped using massively parallel sequencing. Anti P.f. antibodies were evaluated using ELISA. RESULTS: Children carrying the G allele at HLA-F (-1499,rs183540921) showed increased P.f. asymptomatic/symptomatic ratio, suggesting that these children experienced more asymptomatic P.f. episodes than symptomatic one. Children carrying HLA-G-UTR-03 haplotype exhibited increased risk for symptomatic P.f. episodes and showed lower IgG2 response against P.f. GLURP-R2 when compared to the non-carriers. No associations were observed for the HLA-E gene. CONCLUSION: HLA-F associations may be related to the differential expression profiles of the encoded immunomodulatory molecules, and the regulatory sites at the HLA-G 3'UTR may be associated to posttranscriptional regulation of HLA-G and to host humoral response against P.f.

Intravenous Artesunate for the Treatment of Severe Imported Malaria: Implementation, Efficacy, and Safety in 1391 Patients.

BACKGROUND: Intravenous artesunate is the World Health Organization-recommended first-line treatment for severe malaria worldwide, but it is still not fully licensed in Europe. Observational studies documenting its safety and efficacy in imported malaria are thus essential. METHODS: We prospectively collected clinical and epidemiological features of 1391 artesunate-treated patients among 110 participant centers during the first 7 years (2011-2017) of a national program implemented by the French Drug Agency. RESULTS: Artesunate became the most frequent treatment for severe malaria in France, rising from 9.9% in 2011 to 71.4% in 2017. Mortality was estimated at 4.1%. Treatment failure was recorded in 27 patients, but mutations in the Kelch-13 gene were not observed. Main reported adverse events (AEs) were anemia (136 cases), cardiac events (24, including 20 episodes of conduction disorders and/or arrhythmia), and liver enzyme elevation (23). Mortality and AEs were similar in the general population and in people with human immunodeficiency virus, who were overweight, or were pregnant, but the only pregnant woman treated in the first trimester experimented a hemorrhagic miscarriage. The incidence of post-artesunate-delayed hemolysis (PADH) was 42.8% when specifically assessed in a 98-patient subgroup, but was not associated with fatal outcomes or sequelae. PADH was twice as frequent in patients of European compared with African origin. CONCLUSIONS: Artesunate was rapidly deployed and displayed a robust clinical benefit in patients with severe imported malaria, despite a high frequency of mild to moderate PADH. Further explorations in the context of importation should assess outcomes during the first trimester of pregnancy and collect rare but potentially severe cardiac AEs.

Evidence that seasonal malaria chemoprevention with SPAQ influences blood and pre-erythrocytic stage antibody responses of Plasmodium falciparum infections in Niger.

BACKGROUND: In endemic areas, children develop slowly and naturally anti-Plasmodium antibodies and become semi-immune. Seasonal Malaria Chemoprevention (SMC) with sulfadoxine-pyrimethamine + amodiaquine (SPAQ) is a new strategy to reduce malaria morbidity in West African young children. However, SMC may impact on the natural acquisition of anti-Plasmodium immunity. This paper evaluates the effect of SMC with SPAQ on antibody concentration in young children from Niger. METHODS: This research was conducted in areas benefitting from SMC since 2014 (Zinder district), without SMC (Dosso district), and with 1 year of SMC since 2016 (Gaya district). To assess the relationship between SMC and Plasmodium falciparum IgG antibody responses, the total antibody concentrations against two P. falciparum asexual stage vaccine candidate antigens, circumsporozoite protein (CSP) and glutamate-rich protein R2 (GLURP-R2), in children aged 3 to 59 months across the three areas were compared. Antibody concentrations are quantified using an enzyme-linked immunosorbent assay on the elution extracted from positive and negative malaria Rapid Diagnostic Test cassettes. RESULTS: The analysis concerns two hundred and twenty-nine children aged from 3 to 59 months: 71 in Zinder, 77 in Dosso, and 81 in Gaya. In Zinder (CSP = 17.5 µg/ml and GLURP-R2 = 14.3 µg/ml) median antibody concentration observed are higher than in Gaya (CSP = 7.7 µg/ml and GLURP-R2 = 6.5 µg/ml) and Dosso (CSP = 4.5 µg/ml and GLURP-R2 = 3.6 µg/ml) (p < 0.0001). CONCLUSION: The research reveals some evidences which show that seasonal malaria chemoprevention with SPAQ has an effect on blood stage antibody responses and pre-erythrocytic stage of P. falciparum infections in Niger. Increased antibody titres with increased SMC/SPAQ implementation. This contradicts hypothesis that SMC/SPAQ could reduce immunity to erythrocyte and liver-stage antigens. Further studies are necessary to provide better understanding of the SMC effect on malaria immunity.