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Host responses to infection with the malaria parasite Plasmodium falciparum vary among individuals for reasons that are poorly understood. Here we reveal metabolic perturbations as a consequence of malaria infection in children and identify an immunosuppressive role of endogenous steroid production in the context of P. falciparum infection. We perform metabolomics on matched samples from children from two ethnic groups in West Africa, before and after infection with seasonal malaria. Analysing 306 global metabolomes, we identify 92 parasitaemia-associated metabolites with impact on the host adaptive immune response. Integrative metabolomic and transcriptomic analyses, and causal mediation and moderation analyses, reveal an infection-driven immunosuppressive role of parasitaemia-associated pregnenolone steroids on lymphocyte function and the expression of key immunoregulatory lymphocyte genes in the Gouin ethnic group. In children from the less malaria-susceptible Fulani ethnic group, we observe opposing responses following infection, consistent with the immunosuppressive role of endogenous steroids in malaria. These findings advance our understanding of P. falciparum pathogenesis in humans and identify potential new targets for antimalarial therapeutic interventions.

Aim: The present study aimed to evaluate the Plasmodium falciparum genetic diversity according to the host hemoglobin and G6PD genetic variants during the course of malaria in infected children aged from 2 to 10 years and living in endemic area in Burkina Faso. Study Design: The study was designed as a longitudinal follow up conducted between May 2015 and February 2016 in Banfora health district, Burkina Faso. Methodology: We included 136 subjects (73 males and 63 females; age range from 2-10 years). Blood thick and thin film was done by capillary blood. Venous blood was collected for DNA extraction. Malaria diagnosis was done by microscopy. Human and parasite DNA were extracted based on Qiagen kit procedure. Then, hemoglobin and G6PD were genotyped by RLFP-PCR while the msp1, msp2 and eba175 genes were typed by a nested PCR. All PCR products were analyzed by electrophoresis on a 1.5-2% agarose gel and alleles categorized according to the molecular weight. Results: The prevalence of hemoglobin type was 19.11% for abnormal hemoglobin and 80.9% for normal hemoglobin carriage. The prevalence of G6PD type was 91.18% for normal and 8.82% for G6PD deficiency carriage, respectively. The prevalence of msp1 allelic families was 81.60%, 80.80% and 67.20% for k1, ro33 and mad20 respectively while for msp2 gene, fc27 and 3D7 allelic family the prevalence was 70.53% and 69.64% respectively. The eba175 allelic families’ distribution showed 77.31% and 40.21% for fcr3 and Camp respectively. There was no difference in multiplicity of infection (MOI) according to hemoglobin genotypes and G6PD types. We found that k1 was the predominant allelic family of msp1 in normal hemoglobin genotype (AA) and normal G6PD type. The mixed infection of eba175 was statistically higher in abnormal hemoglobin (p=0.04). There was no statistical difference between fcr3 and camp prevalence excepted in G6PD deficient type. The polymorphism results showed that the prevalence of 450 bp in fc27 was statistically significantly higher in normal hemoglobin variant carriers (AA) than abnormal hemoglobin carriers (p=2.10 -4)). However, the prevalence of 350 bp in fc27 was statistically higher in normal G6PD than deficient G6PD carriers (p=0.034). Conclusion: Our result showed that the distribution of msp1 and eba75 polymorphism could be influenced by hemoglobin and G6PD variants. These results suggest that hemoglobin and G6PD could influence P. falciparum genetic diversity.

Introduction: In spite of considerable progress, malaria remains a public health problem in many areas, particularly in sub-Saharan Africa. One major complexity of malaria disease is caused by the development and the spread of vector and parasite resistance to insecticides and antimalarial drugs respectively. The Pfcrt76T gene mutation has been validated as a marker conferring resistance to chloroquine and other antimalarial drugs. The extension of Plasmodium falciparum resistance to commonly used antimalarial drugs (chloroquine, sulfadoxine-pyrimethamine) led to the adoption and the use of artemisinin-based combinations in Burkina Faso since 2005. Aims: The present study was initiated to assess the prevalence of the Pfcrt76T mutation in two different malaria epidemiological setting after a decade of introduction of artemisinin-based combination therapies (ACTs) in Burkina Faso. Methodology: The study population consisted of 181 uncomplicated malaria patients recruited in Banfora and Saponé health districts in 2012 and 2013. Blood samples were collected from finger prick on filter paper, dried and sent to the Molecular Biology Laboratory at Centre National de Recherche et de Formation sur le Paludisme (CNRFP) for molecular analyzes. DNA of Plasmodium falciparum was extracted with DNA extraction kit (Qiagen®) and the Pfcrt76T mutation was determined based on Polymerase Chain Reaction / Restriction Fragment Length Polymorphism technique (RFLP). Results: The results of this study showed that the frequency of the pfcrt76T mutant allele (33.7%) was statistically lower than the Pfcrt76K wild-type allele (57.4%) in the study area. Moreover, the prevalence of Pfcrt76T mutation was neither associated with the patient age nor with the parasite density while a significant difference was observed between the two epidemiological setting, Banfora and Saponé. Conclusion: The findings of this study has shown a drop in the prevalence of mutant parasites Pfcrt76T in both the study area eight years after the introduction of ACTs compared to previous studies.

Aims: The aim of this study is to assess the prevalence of hemoglobin abnormalities and G6PD deficiency and their respective influence on anemia occurring in less than five years old children with clinical P. falciparum malaria living in Burkina Faso. Study Design: The study was a cross-sectional survey with descriptive focus conducted from December 2010 to January 2013 in Saponé health district and from May to October 2011 in Banfora health district. Clinical and laboratory data were collected. Blood smears on slides for malaria diagnosis by microscopy, hemoglobin level and filter paper for the detection of human genetic factors were performed. Methodology: A total of 386 subjects from Saponé (131) and Banfora (255) were enrolled. DNA collected from each sample was extracted using chelex-100 method and the human genetic resistance factors background was assessed by RFLP-PCR. Abnormal hemoglobin patients were classified as NonAA while AA was defined the normal hemoglobin. Results: In this study, 70.98% (274/386) were classified normal hemoglobin (AA) while 29.02% (112/386) of subjects were carrying at least one abnormal (NonAA) allele: 24.35%AC, 3.63% AS, 0.78%CC and 0.26%SC. G6PD deficiency was 9.59% (37/386) among which, 4.92% for male and 4.66% in female. However, this gender difference was not statistically significant (p=1.00). 319/367 (86.92%) of the patients were anemic (59.4% with moderate anemia and 20.98% with mild anemia). The prevalence of anemia in G6PD deficient subjects was 83.33% (of which 58.33% were moderate anemia and 22.22% mild anemia). The difference between types of hemoglobin (p=0.64) in the occurrence of anemia (AA 87.64% and Non AA 85.18%) was not statistically significant. Conclusion: This study showed that the prevalence of these genetic factors was relatively low among children with clinical falciparum malaria with high parasite density. In addition, these factors appear to have no effect on anemia.

Aims: The aim of this study was to assess the impact of hemoglobin polymorphisms and G6PD deficiency on the course of uncomplicated malaria infection in children aged from 2 to 10 years in Burkina Faso. Study Design: The study was conducted as a longitudinal study in Banfora health district. A total of 150 children aged from 2 to 10 years was enrolled and followed up between May 2015 and February 2016. Blood samples were collected at four different time points: before infection (Visit 1), during asymptomatic parasitemia (Visit 2), during symptomatic parasitemia (Visit 3) and three weeks after treatment (Visit 4). Clinical examination, hematology parameters and malaria diagnosis using microscopy were performed. Hemoglobin and G6PD typing were done using PCR-RFLP. Hemoglobin AA genotypes were defined as normal hemoglobin while Hemoglobin AC, AS and SS were defined as abnormal hemoglobin (hb non-AA). Results: The prevalence of hemoglobin (hb) genotypes was 81.21% for AA while hb non-AA genotypes were estimated at 18.79% (12.08% for hbAC, 6.04% for hbAS and 0.67% for HbSC). The prevalence of G6PD genotypes was 89.26% and 10.74% for normal G6PDn and G6PD deficiency respectively. The prevalence of asymptomatic carriers of P. falciparum was not affected neither by the genotypes of Hemoglobin, nor by the G6PD deficiency. Conversely, the risks of developing uncomplicated malaria in G6PD deficiency (G202A) group, was significantly lower (p = 0.04). The results showed a significant difference (p˂0.0001) in the means of P. falciparum parasite densities between asymptomatic and symptomatic phase in Hemoglobin AA genotypes carriers while the means of parasite density was comparable in non-Hemoglobin AA carriers. Conclusion: Our study showed that G6PD deficiency protects against clinical malaria while P. falciparum parasite density increasing was correlated with carrying hemoglobin genotypes AA.

Background The aim of this study was to determine the resistance of diarrheagenic Escherichia coli strains to β-lactams antibiotics and to perform the molecular characterization of Extended Spectrum β-lactamases (ESBL) and integrons genes. Methods This study was carried out from August 2013 to October 2015 and involved 31 DEC strains isolated from diarrheal stools samples collected from children less than five years of age. The identification and characterization of DEC strains was done through the standard biochemical tests those were confirmed using API 20E and Polymerase Chain Reaction (PCR). The determination of antimicrobial resistance was realized by the disk diffusion method then an amplification of the β-lactamase resistance genes and integrons by PCR was done. Results Out of the 419 E. coli strains identified, 31 isolates (7.4%) harbored the DEC virulence genes. From these DEC, 21 (67.7%) were ESBL-producing E. coli. Susceptibility to ESBL-producing E. coli showed that the majority of isolates were highly resistant to amoxicillin (77.4%), amoxicillin clavulanic acid (77.4%) and piperacillin (64.5%). The following antibiotic resistance genes and integron were identified from the 31 DEC isolates: blaTEM (6.5%), blaSHV (19.4%), blaOXA (38.7%) blaCTX−M (9.7%), Int1 (58.1%) and Int3 (19.4%). No class 2 integrons (Int2) was characterized. Conclusions Because of the high prevalence of multidrug-resistant ESBL organisms found in this study among pediatric patients, there is a need of stringent pediatric infection control measures.

Plasmodium falciparum gametocyte kinetics and infectivity may differ between chronic and incident infections. In the current study, we assess parasite kinetics and infectivity to mosquitoes among children (aged 5–10 years) from Burkina Faso with (a) incident infections following parasite clearance (n = 48) and (b) chronic asymptomatic infections (n = 60). In the incident infection cohort, 92% (44/48) of children develop symptoms within 35 days, compared to 23% (14/60) in the chronic cohort. All individuals with chronic infection carried gametocytes or developed them during follow-up, whereas only 35% (17/48) in the incident cohort produce gametocytes before becoming symptomatic and receiving treatment. Parasite multiplication rate (PMR) and the relative abundance of ap2-g and gexp-5 transcripts are positively associated with gametocyte production. Antibody responses are higher and PMR lower in chronic infections. The presence of symptoms and sexual stage immune responses are associated with reductions in gametocyte infectivity to mosquitoes. We observe that most incident infections require treatment before the density of mature gametocytes is sufficient to infect mosquitoes. In contrast, chronic, asymptomatic infections represent a significant source of mosquito infections. Our observations support the notion that malaria transmission reduction may be expedited by enhanced case management, involving both symptom-screening and infection detection., In this longitudinal study of an incident (new infections) and chronic (asymptomatic infections) cohort of Plasmodium falciparum infection in children in Burkina Faso, the authors show higher gametocyte production and mosquito infectivity in chronic infections.

Host responses to infection with the malaria parasite Plasmodium falciparum vary among individuals for reasons that are poorly understood. Here we reveal metabolic perturbations as a consequence of malaria infection in children and identify an immunosuppressive role of endogenous steroid production in the context of P. falciparum infection. We perform metabolomics on matched samples from children from two ethnic groups in West Africa, before and after infection with seasonal malaria. Analysing 306 global metabolomes, we identify 92 parasitaemia-associated metabolites with impact on the host adaptive immune response. Integrative metabolomic and transcriptomic analyses, and causal mediation and moderation analyses, reveal an infection-driven immunosuppressive role of parasitaemia-associated pregnenolone steroids on lymphocyte function and the expression of key immunoregulatory lymphocyte genes in the Gouin ethnic group. In children from the less malaria-susceptible Fulani ethnic group, we observe opposing responses following infection, consistent with the immunosuppressive role of endogenous steroids in malaria. These findings advance our understanding of P. falciparum pathogenesis in humans and identify potential new targets for antimalarial therapeutic interventions.

We longitudinally assessed P. falciparum parasite kinetics, gametocyte production and infectivity in incident infections that were naturally acquired following infection clearance and in chronic asymptomatic infections in Burkina Faso. 92% (44/48) of the incident cohort developed symptoms and were treated within 35 days, compared to 23% (14/60) of the chronic cohort. All but two individuals with chronic infection were gametocytaemic at enrollment, whereas only 35% (17/48) in the incident cohort developed gametocytes within 35 days. The relative abundance of ap2-g transcripts was positively associated with conversion to gametocyte production (i.e. the ratio of gametocytes at day 14 to ring stage parasites at baseline) and was higher in chronic infections. Parasite multiplication rate, assessed by daily molecular parasite quantification, was positively associated with prospective gametocyte production. Most incident infections were cleared before gametocyte density was sufficiently high to infect mosquitoes. In contrast, chronic, asymptomatic infections represented a significant source of mosquito infections. If present, gametocytes were significantly less infectious if concurrent with malaria symptoms. Our observations support the notion that malaria transmission reduction may be expediated by enhanced case management, involving both symptom-screening and infection detection.

Diarrheagenic Escherichia coli (DEC) is important bacteria of children's endemic and epidemic diarrhea worldwide. The aim of this study was to determine the prevalence of DEC isolated from stool samples collected from children with acute diarrhea living in Ouagadougou, Burkina Faso. From August 2013 to October 2015, stool samples were collected from 315 children under 5 years of age suffering from diarrhea in the "Centre Medical avec Antenne Chirurgicale (CMA)" Paul VI and the CMA of Schiphra. E. coli were isolated and identified by standard microbiological methods, and the 16-plex PCR method was used to further characterize them. Four hundred and nineteen (419) E. coli strains were characterized, of which 31 (7.4%) DEC pathotypes were identified and classified in five E. coli pathotypes: 15 enteroaggregative E. coli (EAEC) (48.4%), 8 enteropathogenic E. coli (EPEC) (25.8%) with 4 typical EPEC and 4 atypical EPEC, 4 enteroinvasive E. coli (EIEC) (12.9%), 3 enterohemorrhagic E. coli (EHEC) 9.67%, and 1 enterotoxigenic E. coli (ETEC) 3.2%. The use of multiplex PCR as a routine in clinical laboratory for the detection of DEC would be a useful mean for a rapid management of an acute diarrhea in children.

The association betweenP. falciparum eba-175,ama-1, andmsp-3polymorphism in the pathogenicity of malaria disease was investigated. We therefore compared the prevalence of different alleles between symptomatic and asymptomatic malarial children under five years of age living in Burkina Faso. Blood filter papers were collected during the 2008 malaria transmission season from 228 symptomatic and 199 asymptomatic children under five years of age. All patients were living in the rural area of Saponé at about 50 km from Ouagadougou, the capital city of Burkina Faso.P. falciparumparasite DNA was extracted using QIAGEN kits and the alleles diversity was assessed by a nested PCR. PCR products were then digested by restriction enzymes based on already described polymorphic regions of theeba-175,ama-1, andmsp-3genes. The individual alleleseba-175_FCR3andmsp-3_K1frequencies were statistically higher (p<0.0001) in the asymptomatic group compared to the symptomatic ones. No statistically significant difference was noted in the prevalence ofama-1-3D7,ama-1-K1, andama-1-HB3 genotypes between the two groups (p>0.05). The comparative analysis ofP. falciparumgenotypes indicated that the polymorphism ineba-175andmsp-3genotypes varied between asymptomatic and symptomatic clinical groups and may contribute to the pathogenesis of malaria.