Search

Objective To report the prevalence of polyparasitism during pregnancy in the Lambarene region of Gabon and its association with newborn birth weight. Method Pregnant women in their third trimester were recruited in a prospective study between November 2011 and March 2015. Parasite infection status was assessed microscopically in stool, urine and blood samples. Maternal demographic and obstetrical characteristics and newborns anthropometric data were collected. Multivariable logistic regression was used to assess the association between low birth weight and polyparasitism. Results 678 of 927 pregnant women were included for analysis with mean age (SD) of 25 (6.8) years. The analysis showed that 69% (468/678) were infected with at least one parasite (Plasmodium spp., Schistosoma spp., soil-transmitted helminths, filarial infections). This comprised of 38% with monoparasitism and 31% polyparasitism. The proportion of newborn babies with a weight below 2500 g (LBW) in our study was 21% (142/678). Compared to pregnant women without infection, women with monoparasitic infection had adjusted Odds Ratio confidence interval 95% CI (aOR [95%CI]) of 1.6 [0.95-2.73], those with two parasites had aOR 95%CI of 2.63 [1.51-4.62], and those with more than two parasites had aOR of 5.08 [2.5-10.38] for delivering a newborn with low birth weight. Conclusion In Lambarene, an endemic area for multiple parasite infections, there is a high prevalence of polyparasitism in pregnant women. Polyparasitism is associated with low birth weight. Therefore, there is an urgent need for active screening and treatment of parasite infections in pregnant women to assess the potential public health benefit of such interventions.

Gabon carries a high burden of both tuberculosis (TB) and smoking. This study examines the disease characteristics of smoking pulmonary TB patients in Lambaréné. We interviewed adult pulmonary TB patients in Lambaréné, between March 2016 and April 2019. Clinical and biological patient characteristics were collected. Bivariate and logistic regression analyses were performed to assess factors associated with smoking. The mean age of patients included was 31 years (±13). The proportion of smokers in our study was 30% (89/295). Smoking was significantly associated with patient-related diagnostic delay (adjusted odds ratio [AOR] = 8.18; 95% CI = 3.67-19.56), a higher number of pulmonary TB signs and symptoms (AOR = 2.74; 95% CI = 1.18-6.73), and a higher sputum mycobacterial load (AOR = 3.18; 95% CI = 1.33-8.11). The prevalence of smoking among TB patients is high, and leading to aggravated disease as compared with controls. Our study findings suggest that smoking patients should be regularly screened for TB, to reduce diagnostic delay and TB transmission within community. Smoking cessation activities should be included in the national TB control program in Gabon.

Schistosomiasis is a parasitic infection highly prevalent in Central Africa where it is co-endemic with many other parasitic infections, including soil-transmitted helminths (STHs). For its optimal control, there is a need of descriptive epidemiological data for each endemic region. The objective of the present study was to determine the epidemiological situation around schistosomiasis in Lambaréné, Gabon. A cross-sectional study was conducted among schoolchildren. One urine sample per day was collected on three consecutive days for the diagnosis of schistosomiasis using a urine filtration technique. One stool sample was collected for the detection of Schistosoma spp. and STH spp. eggs using the Kato-Katz technique, and for larvae, using the coproculture technique. A total of 614 schoolchildren were included in the analysis. The overall prevalence of schistosomiasis and STH infections was 26% (159/614) and 15% (70/473), respectively. Human-freshwater contact was the main risk factor for schistosomiasis in the area (relative risk (RR) = 2.96 [2.20-4.00], P < 0.001). Hematuria (RR = 5.53 [4.30-7.10], P < 0.001) and proteinuria (RR = 2.12 [1.63-2.75], P < 0.001) as well as infection with Trichuris trichiura (RR = 1.86 [1.33-2.61], P = 0.002) and Ascaris lumbricoides (RR = 1.96 [1.19-3.21], P = 0.039) were associated with an increased risk of schistosomiasis. Trichuris trichiura was the highest prevalent STH species in the area. Our study reports a moderate prevalence for schistosomiasis with human-water contact as the main risk factor, whereas the prevalence of STH infections appears to be low. Our results stress the need for the implementation of WHO recommendations for schistosomiasis control.

The objective of this pilot malacological survey was to identify the snail intermediate hosts for Schistosoma haematobium in endemic rural and semi-urban areas of Gabon. Snails were collected, morphologically identified, and tested for infection by cercarial shedding. Released cercariae were morphologically identified using low-power light microscopy. A total of six species of snails were collected throughout the study area, with Bulinus truncatus, B. forskalii, and Potadoma spp. being the most predominant species collected. Only the Bulinus species were tested for infection by cercarial shedding, of which only B. truncatus shed cercariae. Some B. truncatus shed mammalian schistosome cercariae, while others shed Gymnocephalus cercariae. Our results indicate that B. truncatus appears to be a potential intermediate host of schistosomiasis in Gabon, where cases of S. haematobium, S. guineensis, and S. intercalatum infection are reported. However, it will be important to further understand the species diversity and transmission dynamics of schistosomes.

Some gut microbes have cospeciated with hominids, but whether they further codiversified with human populations is unclear. Here, we identify predominant gut microbial species sharing a parallel evolutionary history with human populations. Patterns of strain transfer between populations are generally consistent with an African origin, and suggest long-term vertical transmission over thousands of generations. We show the same strains also faithfully transmit between mothers and their children. Consistent with the development of intimate symbiosis, species with strongest patterns of codiversification have the smallest genomes. This study reveals long-term fidelity of gut microbiota with human populations through transmission among individuals living in close proximity. Dominance of specific strains in different populations is based in part on vertical transmission and they may provide population-specific health benefits.One-sentence summaryIdentification of gut microbes that codiversified with human populations.

Background Control of schistosomiasis remains a priority in endemic areas. Local epidemiological data are necessary for a tailored control programme, including data on population behaviour in relation to the disease. The objective of this study was to assess schistosomiasis-related knowledge, attitudes and practices in the general population of Lambaréné, a small city in Gabon, in order to optimise the design and implementation of a local control programme that is tailored to need. Methods The study was cross-sectional in nature. Eligible adults and children living in the study area who volunteered (with informed consent) to participate in the study were interviewed using standardised questionnaires, one of which was a simplified version of the primary questionnaire for participants aged 6–13 years. Data on the participants’ knowledge, attitudes and practices that enhance the risk for contracting schistosomiasis were collected. Results A total of 602 participants were included. The mean (± standard deviation) age was 21.2 (± 15.0) years, the female:male gender ratio was 1.6 and 289 (48%) participants completed the simplified version the questionnaire. Of the 602 participants, 554 (92%) reported past or current contact with freshwater, 218 (36%) reported a history of a diagnosis of schistosomiasis and 193 (32%) reported past intake of praziquantel medication. The overall levels of knowledge and adequate attitudes toward schistosomiasis among young adults and adults were 68 and 73%, respectively. The proportion of participants pursuing risk-enhancing practices (REP) was 60% among the whole study population. Location was significantly associated with differences in knowledge and REP levels. A history of confirmed schistosomiasis and larger family size were significantly associated with an increase in good knowledge and REP levels. However, the indication of freshwater-associated activities was only associated with a significant increase in the REP level. Conclusions The results of this survey reveal a high level of population exposure to schistosomiasis, which is in line with known prevalence of schistosomiasis in Lambaréné and its surroundings. The local population has a reasonable level of knowledge of and adequate attitudes toward schistosomiasis but the level of REP is high, particularly in areas where piped water is absent. In terms of interventions, improving hygiene should have the highest priority, but in a context where provision of safe water is difficult to achieve, the effectiveness of praziquantel treatment and the education of at-risk populations on the need for protective behaviours should be a prominent feature of any local control programme. Graphical abstract

Funding Information: T.P.V., P.G.K., and A.A.A. acknowledge financial support from the German Center for Infection Research (DZIF), Clinical Research Group, Lambarene, and a German Science Foundation grant (DFG Ku 775/17-1) for the German African Cooperation Project in Infectiology. Work was supported by UIDB/04046/2020 and UIDP/04046/2020 Centre grants from FCT, Portugal (to BioISI). L.P.-L. is the recipient of a fellowship from BioSys Ph.D. program PD65-2012 (reference number SFRH/BD/142860/2018) from FCT (Portugal). V.M.L. receives support from the Swedish Research Council (grant agreement numbers 2016-01153, 2016-01154, and 2019-01837), the EU/EFPIA/OICR/McGill/KTH/Diamond Innovative Medicines Initiative 2 Joint Undertaking (EUbOPEN grant number 875510), the Swedish Strategic Research Programmes in Diabetes (SFO Diabetes), Stem Cells and Regenerative Medicine (SFO StratRegen), as well as the European Union’s Horizon 2020 research and innovation program U-PGx (grant agreement number 668353). Publisher Copyright: © 2021 American Society for Microbiology. Malaria remains one of the deadliest diseases in Africa, particularly for children. While successful in reducing morbidity and mortality, antimalarial treatments are also a major cause of adverse drug reactions (ADRs). Host genetic variation in genes involved in drug disposition or toxicity constitutes an important determinant of ADR risk and can prime for parasite drug resistance. Importantly, however, the genetic diversity in Africa is substantial, and thus, genetic profiles in one population cannot be reliably extrapolated to other ethnogeographic groups. Gabon is considered a high-transmission country, with more than 460,000 malaria cases per year. Yet the pharmacogenetic landscape of the Gabonese population or its neighboring countries has not been analyzed. Using targeted sequencing, here, we profiled 21 pharmacogenes with importance for antimalarial treatment in 48 Gabonese pediatric patients with severe Plasmodium falciparum malaria. Overall, we identified 347 genetic variants, of which 18 were novel, and each individual was found to carry 87.369.2 (standard deviation [SD]) variants across all analyzed genes. Importantly, 16.7% of these variants were population specific, highlighting the need for high-resolution pharmacogenomic profiling. Between one in three and one in six individuals harbored reduced-activity alleles of CYP2A6, CYP2B6, CYP2D6, and CYP2C8 with important implications for artemisinin, chloroquine, and amodiaquine therapy. Furthermore, one in three patients harbored at least one G6PD-deficient allele, suggesting a considerably increased risk of hemolytic anemia upon exposure to aminoquinolines. Combined, our results reveal the unique genetic landscape of the Gabonese population and pinpoint the genetic basis for interindividual differences in antimalarial drug responses and toxicity. publishersversion published

Diarrheal disease is the second most frequent cause of mortality in children younger than 5 years worldwide, causing more than half a million deaths each year. Our knowledge of the epidemiology of potentially pathogenic agents found in children suffering from diarrhea in sub-Saharan African countries is still patchy, and thereby hinders implementation of effective preventative interventions. The lack of cheap, easy-to-use diagnostic tools leads to mostly symptomatic and empirical case management. An observational study with a total of 241 participants was conducted from February 2017 to August 2018 among children younger than 5 years with diarrhea in Lambaréné, Gabon. Clinical and demographic data were recorded, and a stool sample was collected. The samples were examined using a commercial rapid immunoassay to detect Rotavirus/adenovirus, conventional bacterial culture for Salmonella spp., and multiplex real-time PCR for Cryptosporidium spp., Giardia lamblia, Cyclospora cayetanensis, enterotoxigenic Escherichia coli (ETEC), and enteroinvasive Escherichia coli (EIEC)/Shigella. At least one infectious agent was present in 121 of 241 (50%) samples. The most frequently isolated pathogens were EIEC/Shigella and ETEC (54/179; 30.2% and 44/179; 24.6%, respectively), followed by G. lamblia (33/241; 13.7%), Cryptosporidium spp. (31/241; 12.9%), and Rotavirus (23/241; 9.5%). Coinfection with multiple pathogens was observed in 33% (40/121) of the positive cases with EIEC/Shigella, ETEC, and Cryptosporidium spp. most frequently identified. Our results provide new insight into the possible causes of diarrheal disease in the Moyen-Ogooué region of Gabon and motivate further research on possible modes of infection and targeted preventive measures.

Background Although Schistosoma haematobium infection has been reported to be associated with alterations in immune function, in particular immune hyporesponsiveness, there have been only few studies that have used the approach of removing infection by drug treatment to establish this and to understand the underlying molecular mechanisms. Methods Schistosoma haematobium-infected schoolchildren were studied before and after praziquantel treatment and compared with uninfected controls. Cellular responses were characterized by cytokine production and flow cytometry, and in a subset of children RNA sequencing (RNA-Seq) transcriptome profiling was performed. Results Removal of S haematobium infection resulted in increased schistosome-specific cytokine responses that were negatively associated with CD4+CD25+FOXP3+ T-cells and accompanied by increased frequency of effector memory T-cells. Innate responses to Toll like receptor (TLR) ligation decreased with treatment and showed positive association with CD4+CD25+FOXP3+ T-cells. At the transcriptome level, schistosome infection was associated with enrichment in cell adhesion, whereas parasite removal was associated with a more quiescent profile. Further analysis indicated that alteration in cellular energy metabolism was associated with S haematobium infection and that the early growth response genes 2 and 3 (EGR 2 and EGR3), transcription factors that negatively regulate T-cell activation, may play a role in adaptive immune hyporesponsiveness. Conclusions Using a longitudinal study design, we found contrasting effects of schistosome infection on innate and adaptive immune responses. Whereas the innate immune system appears more activated, the adaptive immunity is in a hyporesponsive state reflected in alterations in CD4+CD25+FOXP3+ T-cells, cellular metabolism, and transcription factors involved in anergy.

Background Helminths can modulate the host immune response to Plasmodium falciparum and can therefore affect the risk of clinical malaria. We assessed here the effect of helminth infections on both the immunogenicity and efficacy of the GMZ2 malaria vaccine candidate, a recombinant protein consisting of conserved domains of GLURP and MSP3, two asexual blood-stage antigens of P. falciparum. Controlled human malaria infection (CHMI) was used to assess the efficacy of the vaccine. Methodology In a randomized, double-blind Phase I clinical trial, fifty, healthy, lifelong malaria-exposed adult volunteers received three doses of GMZ2 adjuvanted with either Cationic Adjuvant Formulation (CAF) 01 or Alhydrogel, or a control vaccine (Rabies) on days (D) 0, D28 and D56, followed by direct venous inoculation (DVI) of 3,200 P. falciparum sporozoites (PfSPZ Challenge) approximately 13 weeks after last vaccination to assess vaccine efficacy. Participants were followed-up on a daily basis with clinical examinations and thick blood smears to monitor P. falciparum parasitemia for 35 days. Malaria was defined as the presence of P. falciparum parasites in the blood associated with at least one symptom that can be associated to malaria over 35 days following DVI of PfSPZ Challenge. Soil-transmitted helminth (STH) infection was assessed by microscopy and by polymerase chain reaction (PCR) on stool, and Schistosoma infection was assessed by microscopy on urine. Participants were considered as infected if positive for any helminth either by PCR and/or microscopy at D0 and/or at D84 (Helm+) and were classified as mono-infection or co-infection. Total vaccine-specific IgG concentrations assessed on D84 were analysed as immunogenicity outcome. Main findings The helminth in mono-infection, particularly Schistosoma haematobium and STH were significantly associated with earlier malaria episodes following CHMI, while no association was found in case of coinfection. In further analyses, the anti-GMZ2 IgG concentration on D84 was significantly higher in the S. haematobium-infected and significantly lower in the Strongyloides stercoralis-infected groups, compared to helminth-negative volunteers. Interesting, in the absence of helminth infection, a high anti-GMZ2 IgG concentration on D84 was significantly associated with protection against malaria. Conclusions Our results suggest that helminth infection may reduce naturally acquired and vaccine-induced protection against malaria. Vaccine-specific antibody concentrations on D84 may be associated with protection in participants with no helminth infection. These results suggest that helminth infection affect malaria vaccine immunogenicity and efficacy in helminth endemic countries., Author summary Helminths, mainly because of their immune regulatory effects, are able to impact the response induced by vaccines. In the context of clinical trial designs that measure accrual of natural infections during follow up or outcome of controlled human malaria infection (CHMI), their effect on vaccine efficacy can be measured. Indeed, most of such clinical trials on malaria vaccine candidates conducted in Africa, especially where the prevalence of helminths is high, have shown a certain limit in their efficacy and immunogenicity, as compared to results observed in European and U.S volunteers. The present analysis assessed the effect of helminths on GMZ2, a malaria vaccine candidate. We found a high level of anti-GMZ2 antibodies among volunteers not infected with helminths and protected against CHMI, indicating efficacy of the candidate vaccine in this population. We found a species-dependent effect of helminths on the level of post-immunization GMZ2-specific IgG concentration, and an association of helminths with an early onset of malaria in CHMI. Our findings reveal that helminths are associated with immunogenicity and may decrease the protective effect of antibodies induced by vaccination. Helminth infection status shall be determined when measuring the immunogenicity and efficacy of malaria vaccine candidates in helminth endemic countries.

Infection with parasitic helminths has been reported to improve insulin sensitivity and glucose homeostasis, lowering the risk for type 2 diabetes. However, little is known about its impact on whole-body lipid homeostasis, especially in obese individuals. For this purpose, a cross-sectional study was carried out in lean and overweight/obese adults residing in the Lambaréné region of Gabon, an area endemic for Schistosoma haematobium. Helminth infection status, peripheral blood immune cell counts, and serum metabolic and lipid/lipoprotein levels were analyzed. We found that urine S. haematobium egg-positive individuals exhibited lower serum total cholesterol (TC; 4.42 vs 4.01 mmol/L, adjusted mean difference [95%CI] -0.30 [-0.68,-0.06]; P = 0.109), high-density lipoprotein (HDL)-C (1.44 vs 1.12 mmol/L, -0.24 [-0.43,-0.06]; P = 0.009) and triglyceride (TG; 0.93 vs 0.72 mmol/L, -0.20 [-0.39,-0.03]; P = 0.022) levels than egg-negative individuals. However, when stratified according to body mass index, these effects were only observed in overweight/obese infected individuals. Similarly, significant negative correlations between the intensity of infection, assessed by serum circulating anodic antigen (CAA) concentrations, and TC (r = -0.555; P, Author summary Infection with parasitic helminths has been reported to be beneficial for metabolic homeostasis by improving insulin sensitivity and lowering the risk for developing type 2 diabetes. Elevated circulating cholesterol and triglyceride levels associated with obesity are also risk factors for cardiometabolic diseases. In the framework of a cross-sectional study conducted in an endemic rural area, we have investigated the impact of infection with Schistosoma hematobium on serum lipid homeostasis in adult individuals with a broad range of body weight. We found that helminth infection is associated with a lower serum total cholesterol (TC), high-density lipoprotein (HDL)-C and triglyceride (TG) levels, especially in overweight/obese individuals. Furthermore, significant negative correlations between the intensity of infection and TC, HDL-C, LDL-C and TG levels were also found in overweight/obese individuals but not in lean subjects. Altogether our study show for the first time that infection with Schistosoma hematobium is associated with an improved serum lipid profile in overweight/obese humans, a feature that may contribute to protection against cardiometabolic diseases in such population. Further investigation is however required to elucidate the underlying molecular mechanisms.

Background Sub-Saharan Africa carries most of the global burden of schistosomiasis. To optimize disease control and reduce morbidity, precise data are needed for control measures adapted to the local epidemiological situation. The objective of this study is to provide baseline information on schistosomiasis dynamics, including praziquantel (PZQ) treatment outcome in children and young adults living in the vicinity of Lambaréné, Gabon. Methods Eligible volunteers were included into a prospective longitudinal study. Urine filtration technique was used to detect eggs in urine for schistosomiasis diagnosis. Subjects were treated with 60 mg of PZQ once per month for three consecutive months, and the outcome was assessed by cure rate (CR) and egg reduction rate (ERR). Results A total of 328 volunteers were enrolled in the study with a mean (± SD) age of 12.2 ± 4.7 years-old. The female-to-male ratio was 0.99. Out of 258 participants in total, 45% had schistosomiasis during the survey and 43% presented with heavy infections. The incidences of haematuria and schistosomiasis were 0.11 and 0.17 person-years, respectively. After the first and third dose of PZQ, overall ERR of 93% and 95% were found, respectively; while the CR were 78% and 88%, respectively. Both ERR (100 vs 88%) and CR (90 vs 68%) were higher among females than males after the first dose. The CR increased for both groups after the third dose to 95% and 80%, respectively. After the first PZQ dose, ERR was higher for heavy compared to light infections (94 vs 89%), while the CR was higher for light than for heavy infections (87 vs 59%). After the third PZQ dose, ERR increased only for light infections to 99%, while CR increased to 98% and 75% for light and for heavy infections, respectively. The reinfection rate assessed at a mean of 44.6 weeks post-treatment was 25%. Conclusions The prevalence of schistosomiasis is moderate in communities living in the vicinity of Lambaréné, where a subpopulation with a high risk of reinfection bears most of the burden of the disease. To improve schistosomiasis control in this scenario, we suggest education of these high-risk groups to seek themselves a one-year PZQ treatment. Trial registration clinicaltrials.gov Identifier NCT 02769103. Registered 11 May 2016, retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT02769013

Background Malaria burden remains high in the sub-Saharan region where helminths are prevalent and where children are often infected with both types of parasites. Although the effect of helminths on malaria infection is evident, the impact of these co-infections is not clearly elucidated yet and the scarce findings are conflicting. In this study, we investigated the effect of schistosomiasis, considering soil-transmitted helminths (STH), on prevalence and incidence of Plasmodium falciparum infection. Methodology This longitudinal survey was conducted in school-age children living in two rural communities in the vicinity of Lambaréné, Gabon. Thick blood smear light microscopy, urine filtration and the Kato-Katz technique were performed to detect malaria parasites, S. haematobium eggs and, STH eggs, respectively. P. falciparum carriage was assessed at inclusion, and incidence of malaria and time to the first malaria event were recorded in correlation with Schistosoma carriage status. Stratified multivariate analysis using generalized linear model was used to assess the risk of plasmodium infection considering interaction with STH, and survival analysis to assess time to malaria. Main findings The overall prevalence on subject enrolment was 30%, 23% and 9% for S. haematobium, P. falciparum infections and co-infection with both parasites, respectively. Our results showed that schistosomiasis in children tends to increase the risk of plasmodium infection but a combined effect with Trichuris trichiura or hookworm infection clearly increase the risk (aOR = 3.9 [95%CI: 1.7–9.2]). The incidence of malaria over time was 0.51[95%CI: 0.45–0.57] per person-year and was higher in the Schistosoma-infected group compared to the non-infected group (0.61 vs 0.43, p = 0.02), with a significant delay of time-to first-malaria event only in children aged from 6 to 10-years-old infected with Schistosoma haematobium. Conclusions Our results suggest that STH enhance the risk for P. falciparum infection in schistosomiasis-positive children, and when infected, that schistosomiasis enhances susceptibility to developing malaria in young children but not in older children., Author summary Despite the progress made in the last decade, malaria remains a serious public health issue in sub-Saharan region, where it overlaps with helminths infections. The interactions between both are manifold and complex, requiring further investigation. We report here that Trichuris trichiura or hookworm associated with schistosomiasis increase the risk of Plasmodium falciparum infection; whilst schistosomiasis is independently associated with a malaria increase in young children, but not in the older children. Our finding is an additional evidence that optimizing helminth control mainly in children contributes to overcoming malaria in areas endemic for both parasitic infections where children are those who bear the highest burden of these infections.

An estimated 40 million women of childbearing age suffer from schistosomiasis. Animal models indicate a deleterious effect of maternal schistosomiasis on pregnancy outcomes. To date there is a lack of epidemiological evidence evaluating schistosomiasis-related morbidity in pregnancy. This study was designed to describe the impact of urogenital schistosomiasis on pregnancy outcomes in a highly endemic region of central Africa. Pregnant women attending antenatal clinics in Fougamou and Lambaréné, Gabon, were consecutively screened for the presence of Schistosoma haematobium eggs in diurnal urine samples. Maternal and newborn characteristics assessed at delivery were compared between infected and uninfected mothers. The impact of maternal schistosomiasis on low birth weight and preterm delivery was assessed using logistic regression analysis. Urogenital schistosomiasis was diagnosed in 103 (9%) of 1115 pregnant women. Maternal age was inversely associated with the prevalence of urogenital schistosomiasis, with a higher burden amongst nulliparous women. Low birth weight was more common amongst infants of S. haematobium-infected mothers. This association was unaffected by controlling for demographic characteristics, gestational age and Plasmodium infection status (adjusted Odds Ratio 1.93; 95% confidence interval: 1.08-3.42). Other risk factors associated with low birth weight delivery were underweight mothers (adjusted Odds Ratio 2.34; 95% confidence interval: 1.12-4.92), peripheral or placental Plasmodium falciparum infection (adjusted Odds Ratio 2.04; 95% confidence interval: 1.18-3.53) and preterm birth (adjusted Odds Ratio 3.12; 95% confidence interval: 1.97-4.96). Preterm delivery was not associated with S. haematobium infection (adjusted Odds Ratio 1.07 95% confidence interval: 0.57-1.98). In conclusion, this study indicates that pregnant women with urogenital schistosomiasis are at an increased risk for low birth weight deliveries. Further studies evaluating targeted treatment and prevention programmes for urogenital schistosomiasis in pregnant women and their impact on delivery outcomes are warranted.

In many tropical areas schistosomiasis is a major health problem causing hepatosplenic, intestinal or urogenital complaints. Hepatosplenic schistosomiasis mansoni is also characterized by blood coagulation abnormalities. Liver pathology plays a role in the development of haemostatic changes and the parasitic infection may directly affect coagulation. However, these contributing factors cannot be studied separately in hepatosplenic schistosomiasis infections. This pilot study provides insight in haemostatic changes in urinary schistosomiasis by studying coagulation parameters in schistosomiasis haematobium-infected Gabonese schoolchildren. Selection on urinary schistosomiasis patients without hepatosplenic complaints allows for the investigation of the direct effects of the parasite on haemostasis. Levels of von Willebrand Factor (VWF) antigen, active VWF and osteoprotegerin were elevated, indicating inflammation-mediated endothelial activation. In contrast to hepatosplenic schistosomiasis, thrombin–antithrombin complex and D-dimer levels were not affected. Despite its small sample size, this study clearly indicates that Schistosoma haematobium directly alters the activation status of the endothelium, without initiation of coagulation.

BackgroundHuman hookworm infection is a major public health issue in tropical low and middle-income countries with severe consequences. To date, improvement of water supply, sanitation, and hygiene is the major contributor to disease control, and additional control tools are needed. Here, we assess a phase I trial of a new hookworm vaccine candidate Na-APR-1 (M74)/Alhydrogel and Na-GST-1/Alhydrogel in Gabonese school-age children.MethodsA double-blind, randomised, controlled, dose-escalation phase I clinical trial that aims to evaluate safety, reactogenicity and immunogenicity of Na-APR-1 (M74)/Alhydrogel co-administered with Na-GST-1/Alhydrogel hookworm vaccines in children aged 6 to 10 years living in hookworm-endemic area of Lambaréné, compared to the hepatitis B vaccine (ENGERIX-B). Children received three doses of assigned vaccines, delivered intramuscularly (deltoid) on Days 0, 56, and 112 or 180. Safety is measured from Day 0 through Day 14 by the occurrence of solicited injection site and systemic reactogenicity events. Clinical laboratory evaluations were performed approximately 14 days after each immunisation. Unsolicited adverse events were collected from Day 0 through approximately 1 month after each vaccination.ResultsA total of 135 children were screened, and 60, aged 6 to 10 years old, were randomised into 3 groups and received 10 µg, 30 µg or 100 µg of Na-APR-1 (M74)/Alhydrogel and Na-GST-1 Alhydrogel, respectively, compared to ENGERIX-B. At baseline, the mean age of the study population was 7.4 years and the sex ratio 1.3 (male: female). From Day 0 up to Day 14 after vaccination, the main solicited adverse events were pain and swelling at injection sites with 135 (26 of grade 2 and 1 of grade 3) and 9 events, respectively. Regarding systemic adverse events, 3 occurrences of grade 1 headache were recorded. Immunogenicity analyses are underway.ConclusionThe preliminary results confirm that co-administration of the two hookworm vaccine candidates is safe and well-tolerated in Gabonese children.

BackgroundIn sub-Saharan Africa, Plasmodium spp. infection prevalence very often overlaps with helminth infections, particularly with schistosomiasis which is reported to be the second parasitic infection after malaria in terms of prevalence. Interaction between both infections has been reported earlier. Schistosomiasis is typically a chronic disease, whereas malaria occurs in episodes, particularly in children. In this study, we assessed the effect of Schistosoma haematobium infection on clinical malaria among children.MethodsA longitudinal study was conducted from June 2016 to February 2018. Volunteers without any known chronic condition were included. Thick blood smear (TBS) was performed monthly at participants’ homes. For any medical concern including malaria-like symptoms and visible haematuria, participants were invited to come to CERMEL for diagnosis and treatment. Light microscopy was performed to detect malaria parasites and Schistosoma eggs, using TBS and urine filtration technique, respectively. Over the study course, participants found to be infected were treated accordingly. Schistosomiasis status was determined at the end of the follow-up.ResultsAmong the 351 volunteers included in the study, schistosomiasis status was available for 260. Mean age was 12.3 year (SD 4.6) with a 0.96 women-to-men sex ratio. Of those, 112/260 (43.1%) [37.0%–49.3%] participants were positive for S. haematobium, and a total of 132 (51%) children developed 230 malaria attacks. Those with schistosomiasis had a 1.5:1 [1.1–2.0] risk to develop malaria compared to their uninfected counterparts. The mean number of malaria episodes per child over the study course was higher among children with schistosomiasis compared to those without (2.03 vs 1.57, p-value=0.015).ConclusionS. haematobium infection was associated with increased susceptibility to develop malaria (by increasing the risk to develop a malaria episode) and, consequently, a higher malaria incidence.

BackgroundSchistosomiasis is a highly prevalent parasitic infection in Central Africa, where co-endemicity with other parasitic infections is common, and schistosomiasis outcomes can be affected by those other infections. Therefore, proper schistosomiasis control needs epidemiological data accounting for co-infections, too. In this present study, our objective was to determine the epidemiological situation around schistosomiasis in Lambaréné.MethodsA cross-sectional study was conducted among school-aged children living in Lambaréné. Urine filtration exam was performed for the detection of Schistosoma eggs. Kato-Katz and stool culture (Coproculture and Harada-Mori) techniques were used for the detection of soil-transmitted helminths. Detection of Plasmodium spp. and blood microfilariae was performed applying light microscopy. Risk factors for schistosomiasis and factors associated with schistosomiasis were investigated; haematology parameters evaluated.ResultsA total of 614 school children with available schistosomiasis status were included in the analysis. Mean age was 10.9 (SD=2.7) years, with a 0.95 boy-to-girl sex ratio. The prevalence of schistosomiasis was 26%. No risk factors except human-water contact were associated with schistosomiasis. Only Trichuris trichiura co-infection was associated with an increased odd (aOR=2.3, p-value=0.048) to be infected with schistosomiasis. Full blood counts showed a decrease of haemoglobin level and increase of WBC and platelet levels among the schistosoma-infected children. Haematuria was found associated with schistosomiasis (aOR=14.5, p-valueConclusionThe prevalence of schistosomiasis is moderate in Lambaréné where human-water contact remains the main risk factor and praziquantel is available for treatment. Trichuriasis is associated with increased risk to be infected. Children with schistosomiasis exhibit a distinct full blood count profile and haematuria is found to be more suitable to predict infection. However, it is desirable to implement comprehensive approaches beyond chemotherapy for schistosomiasis control in this area as recommended by WHO.

BackgroundDiarrhoeal disease remains the second leading cause of death in children under five years, being associated with about 525,000 deaths every year. The most common pathogens worldwide are Shigella spp/EIEC, rotavirus, adenovirus 40/41, ST-ETEC and Cryptosporidium spp. Public health interventions rely on estimates of pathogen-specific burden for prioritisation. Sadly, comprehensive data on the aetiology of diarrhoea in children is lacking for Gabon. This study aimed to identify the spectrum of pathogens found in Lambaréné, Gabon and provide baseline data on their prevalence, needed for implementation of effective control measures.MethodsA cross-sectional study was conducted at Albert Schweitzer and Georges Rawiri Regional hospitals in Lambaréné from February 2017 to February 2018. A consecutive sample of children under 5 year old with diarrhoea or a history of diarrhoea within the previous three days were prospectively studied. A single stool sample was collected from each study participant and processed using commercial rapid immunoassays to detect antigens of rotavirus, adenovirus, and Cryptosporidium spp. Multiplex PCR was used for Cryptosporidium spp., Giardia lamblia and Cyclospora cayetanensis detection, and characterisation of E. coli strains.ResultsOut of 188 participants who provided stool samples, one or more pathogens could be detected in 34.6% of the cases. The most prevalent parasites were Giardia lamblia (14.9%), Cryptosporidium spp. (11.7%), and Cyclospora cayetanensis (2.7%). Enteric viruses also were identified in these children: 10.6% and 1.6% of rotavirus and adenovirus, respectively. Multiple pathogens were detected in 5.3% of samples.ConclusionThis analysis of the causes of diarrhoea in children under 5 years of age in our setting showed three main pathogens: Giardia lamblia, Cryptosporidium spp. and rotavirus. Our study confirms major agents of acute diarrhoeal diseases in children, highlights research needs (Cryptosporidium) and supports the introduction of new tools such as the implementation of the rotavirus vaccine in the national immunisation programme.

Background Current artesunate (ARS) regimens for severe malaria are complex. Once daily intramuscular (i.m.) injection for 3 d would be simpler and more appropriate for remote health facilities than the current WHO-recommended regimen of five intravenous (i.v.) or i.m. injections over 4 d. We compared both a three-dose i.m. and a three-dose i.v. parenteral ARS regimen with the standard five-dose regimen using a non-inferiority design (with non-inferiority margins of 10%). Methods and Findings This randomized controlled trial included children (0.5–10 y) with severe malaria at seven sites in five African countries to assess whether the efficacy of simplified three-dose regimens is non-inferior to a five-dose regimen. We randomly allocated 1,047 children to receive a total dose of 12 mg/kg ARS as either a control regimen of five i.m. injections of 2.4 mg/kg (at 0, 12, 24, 48, and 72 h) (n = 348) or three injections of 4 mg/kg (at 0, 24, and 48 h) either i.m. (n = 348) or i.v. (n = 351), both of which were the intervention arms. The primary endpoint was the proportion of children with ≥99% reduction in parasitemia at 24 h from admission values, measured by microscopists who were blinded to the group allocations. Primary analysis was performed on the per-protocol population, which was 96% of the intention-to-treat population. Secondary analyses included an analysis of host and parasite genotypes as risks for prolongation of parasite clearance kinetics, measured every 6 h, and a Kaplan–Meier analysis to compare parasite clearance kinetics between treatment groups. A post hoc analysis was performed for delayed anemia, defined as hemoglobin ≤ 7g/dl 7 d or more after admission. The per-protocol population was 1,002 children (five-dose i.m.: n = 331; three-dose i.m.: n = 338; three-dose i.v.: n = 333); 139 participants were lost to follow-up. In the three-dose i.m. arm, 265/338 (78%) children had a ≥99% reduction in parasitemia at 24 h compared to 263/331 (79%) receiving the five-dose i.m. regimen, showing non-inferiority of the simplified three-dose regimen to the conventional five-dose regimen (95% CI −7, 5; p = 0.02). In the three-dose i.v. arm, 246/333 (74%) children had ≥99% reduction in parasitemia at 24 h; hence, non-inferiority of this regimen to the five-dose control regimen was not shown (95% CI −12, 1; p = 0.24). Delayed parasite clearance was associated with the N86YPfmdr1 genotype. In a post hoc analysis, 192/885 (22%) children developed delayed anemia, an adverse event associated with increased leukocyte counts. There was no observed difference in delayed anemia between treatment arms. A potential limitation of the study is its open-label design, although the primary outcome measures were assessed in a blinded manner. Conclusions A simplified three-dose i.m. regimen for severe malaria in African children is non-inferior to the more complex WHO-recommended regimen. Parenteral ARS is associated with a risk of delayed anemia in African children. Trial registration Pan African Clinical Trials Registry PACTR201102000277177, In a randomized trial, Sanjeev Krishna and colleagues test for non-inferiority of a simplified artemisinin regimen as treatment for malaria in a low-resource setting., Editors' Summary Background Globally, about 200 million cases of malaria—a mosquito-borne parasitic disease—occur every year. Malaria infections, which can be caused by several parasites, can be “uncomplicated” or “severe.” Prompt treatment of uncomplicated malaria, which presents with flu-like symptoms, is essential to prevent the development of severe malaria. The World Health Organization (WHO) recommends artemisinin combination therapy (ACT) for the first-line treatment of uncomplicated malaria in countries where the disease is always present. In ACT, artemisinin derivatives (fast-acting antimalarial drugs that are cleared rapidly from the body) are combined with a slower-acting, more slowly eliminated partner drug to prevent the original infection recurring and to reduce the risk of the malaria parasites becoming resistant to either drug. Severe malaria, which is usually caused by Plasmodium falciparum, is characterized by anemia and by damage to the brain and other organs. Severe malaria kills more than 400,000 people (mainly young children living in sub-Saharan Africa) every year. Why Was This Study Done? WHO recommends that severe malaria be treated with intravenous or intramuscular injections of artesunate, a parenteral (injectable) form of artemisinin; patients with severe malaria cannot take pills reliably or safely. Specifically, WHO recommends that patients be given 2.4 mg of artesunate per kilogram of body weight intravenously or intramuscularly at the time of admission (0 hours) and at 12, 24, 48, and 72 hours (followed by ACT to ensure full parasite clearance). But this five-dose regimen is complex. A simpler regimen would be easier to administer in resource-limited settings, where giving the correct doses on time to small, sick children can be challenging. In this open-label, non-inferiority randomized controlled trial (RCT), the researchers investigate the efficacy of a three-dose artesunate regimen for the treatment of severe malaria in African children. RCTs compare outcomes in people randomly chosen to receive different interventions; in an open-label RCT, both the researchers and the participants know which treatment is being given; a non-inferiority trial investigates whether one treatment is not worse than another treatment. What Did the Researchers Do and Find? The researchers randomly allocated 1,047 children aged six months to ten years with severe malaria attending seven clinical centers in five African countries to receive a total dose of 12 mg of artesunate per kilogram of body weight as five intramuscular injections of 2.4 mg/kg given at 0, 12, 24, 48, and 72 hours (the control regimen) or as three intramuscular or intravenous injections of 4 mg/kg given at 0, 12, and 24 hours (three-dose intramuscular and intravenous regimens, respectively). The trial’s primary endpoint was the proportion of children whose parasitemia (parasite count in the blood) at 24 hours was ≤1% of that at admission (in other words, ≥99% parasite clearance). Among the 1,002 children who received the planned drug doses (the per-protocol population), 78% in the three-dose intramuscular group had ≥99% parasite clearance compared to 79% in the five-dose intramuscular group, a result that met a preset criterion for non-inferiority at 24 hours of the three-dose intramuscular regimen to the control regimen. However, because only 74% of the children in the three-dose intravenous group had ≥99% parasite clearance, this regimen was not shown to be non-inferior to the conventional five-dose regimen. What Do These Findings Mean? These findings when combined with the findings of several secondary analyses suggest that, in African children, a three-dose intramuscular artesunate regimen is non-inferior to the WHO-recommended regimen for the treatment of severe malaria. The study’s open-label design may limit the accuracy of its findings, as may its use of a primary endpoint midway through drug treatment rather than at the end (the researchers note that 60% of deaths from severe malaria occur during the first 24 hours of illness and that parasitemia is harder to measure later during treatment) and its use of parasite clearance rather than death as the primary endpoint (case fatality rates in severe malaria treatment trials are very low, so a much larger study would be needed if death were used as the primary endpoint). Overall, these findings support the use of the three-dose intramuscular artesunate regimen for the treatment of severe malaria. Importantly, however, 22% of the children in the study developed delayed anemia, irrespective of treatment regimen. Thus, although further studies are needed to clarify whether treatment with artesunate or the malaria infection itself was responsible for the delayed anemia, patients treated with artesunate for severe malaria should be routinely monitored for this complication. Additional Information This list of resources contains links that can be accessed when viewing the PDF on a device or via the online version of the article at http://dx.doi.org/10.1371/journal.pmed.1001938. Information is available from the World Health Organization on malaria (in several languages); the World Malaria Report 2014 provides details of the current global malaria situation, including information on malaria in individual African countries; WHO’s Guidelines for the Treatment of Malaria and its Management of Severe Malaria: A Practical Handbook are available The US Centers for Disease Control and Prevention provides information on malaria (in English and Spanish), including personal stories about malaria The UK National Health Service Choices website also provides information about malaria, including a personal story Information is available from the Roll Back Malaria Partnership on the global control of malaria The Scientists Against Malaria collaboration applies modern drug design and modeling techniques to develop new treatments against malaria; its website includes information about many aspects of malaria Public Health England provides a collection of guidance and research and analysis on malaria MedlinePlus provides links to additional information on malaria (in English and Spanish) More information about this trial is available

Contains fulltext : 171915.pdf (Publisher’s version ) (Open Access) Infections with helminths and Plasmodium spp. overlap in their geographical distribution. It has been postulated that helminth infections may influence malarial transmission by altering Plasmodium falciparum gametocytogenesis. This cross-sectional study assessed the effect of helminth infections on P. falciparum gametocyte carriage and on humoral immune responses to sexual stage antigens in Gabon. Schistosoma haematobium and filarial infections as well as P. falciparum asexual forms and gametocyte carriage were determined. The antibody responses measured were to sexual (Pfs230, Pfs48/45) and asexual P. falciparum antigens (AMA1, MSP1, and GLURP). A total of 287 subjects were included. The prevalence of microscopically detectable P. falciparum asexual parasites was higher in S. haematobium-infected subjects in comparison to their uninfected counterparts (47% versus 26%, P = 0.003), but this was not different when filarial infections were considered. Plasmodium falciparum gametocyte carriage was similar between Schistosoma- or filaria-infected and uninfected subjects. We observed a significant decrease of Pfs48/45 immunoglobulin G titer in S. haematobium-infected subjects (P = 0.037), whereas no difference was seen for Pfs230 antibody titer, nor for antibodies to AMA1, MSP1, or GLURP. Our findings suggest an effect of S. haematobium on antibody responses to some P. falciparum gametocyte antigens that may have consequences for transmission-blocking immunity.

Urogenital schistosomiaisis is a serious public health problem in sub-Saharan Africa. In this study, we have updated an established real-time polymerase chain reaction (PCR) routinely used in our laboratory. Schistosoma genus-specific real-time PCR was performed on DNA isolated from 85 urine samples and pellets obtained after centrifugation without and after frozen storage. The results revealed that concentration by centrifugation of the urine samples and freezing of the samples before extracting DNA improves the sensitivity of the PCR.

In many regions where soil-transmitted helminth infections are endemic, single-dose albendazole is used in mass drug administration programs to control infections. There are little data on the efficacy of the standard single-dose administration compared to that of alternative regimens. We conducted a randomized, controlled, assessor-blinded clinical trial to determine the efficacies of standard and extended albendazole treatment against soil-transmitted helminth infection in Gabon. A total of 175 children were included. Adequate cure rates and egg reduction rates above 85% were found with a single dose of albendazole for Ascaris infection, 85% (95% confidence interval [CI], 73, 96) and 93.8% (CI, 87.6, 100), respectively, while two doses were necessary for hookworm infestation (92% [CI, 78, 100] and 92% [CI, 78, 100], respectively). However, while a 3-day regimen was not sufficient to cure Trichuris (cure rate, 83% [CI, 73, 93]), this regimen reduced the number of eggs up to 90.6% (CI, 83.1, 100). The rate ratios of two- and three-dose regimens compared to a single-dose treatment were 1.7 (CI, 1.1, 2.5) and 2.1 (CI, 1.5, 2.9) for Trichuris and 1.7 (CI, 1.0, 2.9) and 1.7 (CI, 1.0, 2.9) for hookworm. Albendazole was safe and well tolerated in all regimens. A single-dose albendazole treatment considerably reduces Ascaris infection but has only a moderate effect on hookworm and Trichuris infections. The single-dose option may still be the preferred regimen because it balances efficacy, safety, and compliance during mass drug administration, keeping in mind that asymptomatic low-level helminth carriage may also have beneficial effects. (This study has been registered at ClinicalTrials.gov under registration number NCT01192802.)