A randomized assessors-blind clinical trial to evaluate the safety and the efficacy of albendazole alone and in combination with mebendazole or pyrantel for the treatment of Trichuris trichiura infection in school-aged children in Lambaréné and surroundings.

Helminthiasis remains a public health issue in endemic areas. Various drugs have been proposed to improve efficacy against helminths. The study aimed to assess the safety and efficacy of three different anthelmintic combinations to treat Trichuris trichiura infections. We conducted a randomized assessors-blind clinical trial involving children aged 2-17 years with T. trichiura. Participants were randomly assigned to one of three treatment arms. On the first and third days, all participants got albendazole 400 mg, and on the second day, albendazole (arm A), mebendazole 500 mg (arm B), or pyrantel 125 mg/kg (arm C). We assessed treatment efficacy using the cure rate (CR) and egg reduction rate (ERR) at 3 and 6 weeks post-treatment. At 3 weeks post-treatment, ERR and CR were highest in study arm A [ERR = 94%, 95% confidence interval (CI): 92-95; CR = 71%; 95% CI: 58-81] compared to the B and C arms. Decrease in ERR was significant only for arm B versus arm A (P-value <0.001); decrease in ERR was significant for arms B and C (P-value <0.001). No statistical difference was observed in CR when comparing arms A and B (P-value =1.00) and C (P-value =0.27). At 6 weeks, a decrease in ERR was observed in three arms, significant only for arm C, 81% (95% CI: 78-83). A significant increase in egg counts was observed between 3 and 6 weeks post-treatment. All treatments were safe with mild adverse events. Albendazole 400 mg/day (arm A) showed the highest efficacy against trichuriasis. Nonetheless, this treatment regimen was able to cure half of the treated individuals highlighting concerns about controlling the transmission of T. trichiura.CLINICAL TRIALRegistered at ClinicalTrials.gov (NCT04326868).

Codiversification of gut microbiota with humans.

The gut microbiomes of human populations worldwide have many core microbial species in common. However, within a species, some strains can show remarkable population specificity. The question is whether such specificity arises from a shared evolutionary history (codiversification) between humans and their microbes. To test for codiversification of host and microbiota, we analyzed paired gut metagenomes and human genomes for 1225 individuals in Europe, Asia, and Africa, including mothers and their children. Between and within countries, a parallel evolutionary history was evident for humans and their gut microbes. Moreover, species displaying the strongest codiversification independently evolved traits characteristic of host dependency, including reduced genomes and oxygen and temperature sensitivity. These findings all point to the importance of understanding the potential role of population-specific microbial strains in microbiome-mediated disease phenotypes.

Molecular surveillance and genetic divergence of rotavirus A antigenic epitopes in Gabonese children with acute gastroenteritis.

BACKGROUND: Rotavirus A (RVA) causes acute gastroenteritis in children <5 years of age in sub-Saharan Africa. In this study, we described the epidemiology and genetic diversity of RVA infecting Gabonese children and examined the antigenic variability of circulating strains in relation to available vaccine strains to maximize the public health benefits of introducing rotavirus vaccine through the Expanded Programme on Immunization (EPI) in Gabon. METHODS: Stool samples were collected consecutively between April 2018 and November 2019 from all hospitalized children <5 years with gastroenteritis and community controls without gastroenteritis. Children were tested for rotavirus A by quantitative RT-PCR and subsequently sequenced to identify circulating rotavirus A genotypes in the most vulnerable population. The VP7 and VP4 (VP8*) antigenic epitopes were mapped to homologs of vaccine strains to assess structural variability and potential impact on antigenicity. FINDINGS: Infections were mostly acquired during the dry season. Rotavirus A was detected in 98/177 (55%) hospitalized children with gastroenteritis and 14/67 (21%) of the control children. The most common RVA genotypes were G1 (18%), G3 (12%), G8 (18%), G9 (2%), G12 (25%), with G8 and G9 reported for the first time in Gabon. All were associated either with P[6] (31%) or P[8] (38%) genotypes. Several non-synonymous substitutions were observed in the antigenic epitopes of VP7 (positions 94 and 147) and VP8* (positions 89, 116, 146 and 150), which may modulate the elicited immune responses. INTERPRETATION: This study contributes to the epidemiological surveillance of rotavirus A required before the introduction of rotavirus vaccination in the EPI for Gabonese children.

Prevalence of Pathogens in Young Children Presenting to Hospital with Diarrhea from Lambaréné, Gabon.

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.

Association of low birth weight and polyparasitic infection during pregnancy in Lambaréné, Gabon.

OBJECTIVE: To report the prevalence of polyparasitism during pregnancy in the Lambaréné 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 Lambaréné, 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.

Genetic Diversity of Enteric Viruses in Children under Five Years Old in Gabon.

Enteric viruses are the leading cause of diarrhea in children globally. Identifying viral agents and understanding their genetic diversity could help to develop effective preventive measures. This study aimed to determine the detection rate and genetic diversity of four enteric viruses in Gabonese children aged below five years. Stool samples from children <5 years with (n = 177) and without (n = 67) diarrhea were collected from April 2018 to November 2019. Norovirus, astrovirus, sapovirus, and aichivirus A were identified using PCR techniques followed by sequencing and phylogenetic analyses. At least one viral agent was identified in 23.2% and 14.9% of the symptomatic and asymptomatic participants, respectively. Norovirus (14.7%) and astrovirus (7.3%) were the most prevalent in children with diarrhea, whereas in the healthy group norovirus (9%) followed by the first reported aichivirus A in Gabon (6%) were predominant. The predominant norovirus genogroup was GII, consisting mostly of genotype GII.P31-GII.4 Sydney. Phylogenetic analysis of the 3CD region of the aichivirus A genome revealed the presence of two genotypes (A and C) in the study cohort. Astrovirus and sapovirus showed a high diversity, with five different astrovirus genotypes and four sapovirus genotypes, respectively. Our findings give new insights into the circulation and genetic diversity of enteric viruses in Gabonese children.

Epidemiological, Mycobacteriological, and Clinical Characteristics of Smoking Pulmonary Tuberculosis Patients, in Lambaréné, Gabon: A Cross-Sectional Study.

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.

Performance of a rapid diagnostic test for the detection of Cryptosporidium spp. in African children admitted to hospital with diarrhea.

BACKGROUND: Cryptosporidium is a protozoan parasite that causes mild to severe diarrhoeal disease in humans. To date, several commercial companies have developed rapid immunoassays for the detection of Cryptosporidium infection. However, the challenge is to identify an accurate, simple and rapid diagnostic tool for the estimation of cryptosporidiosis burden. This study aims at evaluating the accuracy of CerTest Crypto, a commercialized rapid diagnostic test (RDT) for the detection of Cryptosporidium antigens in the stool of children presenting with diarrhoea. METHODS: A cross-sectional study was conducted in four study sites in Sub-Saharan Africa (Gabon, Ghana, Madagascar, and Tanzania), from May 2017 to April 2018. Stool samples were collected from children under 5 years with diarrhoea or a history of diarrhoea within the last 24 hours. All specimens were processed and analyzed using CerTest Crypto RDT against a composite diagnostic panel involving two polymerase chain reaction (PCR) tests (qPCR and RFLP-PCR,) as the gold standard. RESULTS: A total of 596 stool samples were collected. Evaluation of the RDT yielded a very low overall sensitivity of 49.6% (confidence interval (CI) 40.1-59.0), a specificity of 92.5% (CI 89.8-94.7), positive predictive value of 61.3% (CI 50.6-71.2), and negative predictive value of 88.5% (85.3-91.1) when compared to the composite reference standard of qPCR and RFLP-PCR for the detection of Cryptosporidium species. Moreover, the performance of this test varied across different sites. CONCLUSION: The weak performance of the studied RDT suggests the need to carefully evaluate available commercial RDTs before their use as standard tools in clinical trials and community survey of Cryptosporidium infections in pediatric cohorts.

Diagnostic Techniques of Soil-Transmitted Helminths: Impact on Control Measures.

Soil-transmitted helminth (STH) infections are common in the tropical and subtropical countries. The burden of disease is highest in endemic areas with limited access to good quality water supply and poor sanitary conditions. Major approaches to control and reduce morbidity caused by worm infections include the periodic deworming of pre-school and school-aged children with anthelminthic drugs. Population-based studies and individual patient management including interventional studies can only be successful when accurate diagnostic techniques are used. The lack of appropriate diagnostic tools providing accurate results concerning both infectious status and intensity of infection-as these two factors vary in regions of low infection intensities-is a major challenge. Currently, available techniques show limited sensitivity and specificity and as such, a combination of several techniques is usually used to diagnose the large variety of parasite species. The objective of this review was to describe the advantages and disadvantages of the different available techniques for the diagnosis of STH infections and to highlight their use in control programs.

Monitoring of efficacy, tolerability and safety of artemether-lumefantrine and artesunate-amodiaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Lambaréné, Gabon: an open-label clinical trial.

BACKGROUND: Malaria remains a major public health problem, affecting mainly low-and middle-income countries. The management of this parasitic disease is challenged by ever increasing drug resistance. This study, investigated the therapeutic efficacy, tolerability and safety of artemether-lumefantrine (AL) and artesunate-amodiaquine (AS-AQ), used as first-line drugs to treat uncomplicated malaria in Lambaréné, Gabon. METHODS: A non-randomized clinical trial was conducted between October 2017 and March 2018 to assess safety, clinical and parasitological efficacy of fixed-doses of AL and AS-AQ administered to treat uncomplicated Plasmodium falciparum malaria in children aged from 6 months to 12 years. After 50 children were treated with AL, another 50 children received ASAQ. The 2009 World Health Organization protocol for monitoring of the efficacy of anti­malarial drugs was followed. Molecular markers msp1 and msp2 were used to differentiate recrudescence and reinfection. For the investigation of artemisinin resistant markers, gene mutations in Pfk13 were screened. RESULTS: Per-protocol analysis on day 28 showed a PCR corrected cure rate of 97% (95% CI 86-100) and 95% (95% CI 84-99) for AL and AS-AQ, respectively. The most frequent adverse event in both groups was asthenia. No mutations in the kelch-13 gene associated with artemisinin resistance were identified. All participants had completed microscopic parasite clearance by day 3 post-treatment. CONCLUSION: This study showed that AL and AS-AQ remain efficacious, well-tolerated, and are safe to treat uncomplicated malaria in children from Lambaréné. However, a regular monitoring of efficacy and a study of molecular markers of drug resistance to artemisinin in field isolates is essential. Trial registration ANZCTR, ACTRN12616001600437. Registered 18 November, http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12616001600437p&isBasic=True.

High-throughput analysis of human cytomegalovirus genome diversity highlights the widespread occurrence of gene-disrupting mutations and pervasive recombination.

Human cytomegalovirus is a widespread pathogen of major medical importance. It causes significant morbidity and mortality in the immunocompromised and congenital infections can result in severe disabilities or stillbirth. Development of a vaccine is prioritized, but no candidate is close to release. Although correlations of viral genetic variability with pathogenicity are suspected, knowledge about strain diversity of the 235kb genome is still limited. In this study, 96 full-length human cytomegalovirus genomes from clinical isolates were characterized, quadrupling the available information for full-genome analysis. These data provide the first high-resolution map of human cytomegalovirus interhost diversity and evolution. We show that cytomegalovirus is significantly more divergent than all other human herpesviruses and highlight hotspots of diversity in the genome. Importantly, 75% of strains are not genetically intact, but contain disruptive mutations in a diverse set of 26 genes, including immunomodulative genes UL40 and UL111A. These mutants are independent from culture passaging artifacts and circulate in natural populations. Pervasive recombination, which is linked to the widespread occurrence of multiple infections, was found throughout the genome. Recombination density was significantly higher than in other human herpesviruses and correlated with strain diversity. While the overall effects of strong purifying selection on virus evolution are apparent, evidence of diversifying selection was found in several genes encoding proteins that interact with the host immune system, including UL18, UL40, UL142 and UL147. These residues may present phylogenetic signatures of past and ongoing virus-host interactions. IMPORTANCE: Human cytomegalovirus has the largest genome of all viruses that infect humans. Currently, there is a great interest in establishing associations between genetic variants and strain pathogenicity of this herpesvirus. Since the number of publicly available full-genome sequences is limited, knowledge about strain diversity is highly fragmented and biased towards a small set of loci. Combined with our previous work, we have now contributed 101 complete genome sequences. We have used these data to conduct the first high-resolution analysis of interhost genome diversity, providing an unbiased and comprehensive overview of cytomegalovirus variability. These data are of major value to the development of novel antivirals and a vaccine and to identify potential targets for genotype-phenotype experiments. Furthermore, they have enabled a thorough study of the evolutionary processes that have shaped cytomegalovirus diversity.