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Background: Despite dengue virus (DENV) outbreak in Gabon a decade ago, less is known on the potential circulation of DENV serotypes in the country. Previous studies conducted in some areas of the country, are limited to hospital-based surveys which reported the presence of some cases of serotype 2 and 3 seven years ago and more recently the serotype 1. As further investigation, we extend the survey to the community of Moyen Ogooué region with the aim to assess the presence of the dengue virus serotypes, additionally to characterize chikungunya (CHIKV) infection and describe the symptomatology associated with infections., Method: A cross-sectional survey was conducted from April 2020 to March 2021. The study included participants of both sexes and any age one year and above, with fever or history of fever in the past seven days until blood collection. Eligible volunteers were clinically examined, and blood sample was collected for the detection of DENV and CHIKV using RT-qPCR. Positive samples were selected for the target sequencing., Results: A total of 579 volunteers were included. Their mean age (SD) was 20 (20) years with 55% of them being female. Four cases of DENV infection were diagnosed giving a prevalence of 0.7% (95%CI: 0.2-1.8) in our cohort while no case of CHIKV was detected. The common symptoms and signs presented by the DENV cases included fatigue, arthralgia myalgia, cough, and loss of appetite. DENV-1was the only virus detected by RT-qPCR., Conclusion: Our results confirm the presence of active dengue infection in the region, particularly DENV-1, and could suggest the decline of DENV-2 and DENV-3. Continuous surveillance remains paramount to comprehensively describe the extent of dengue serotypes distribution in the Moyen-Ogooué region of Gabon., (© 2024. The Author(s).)

Objective: Variants of concern (VOCs) associated with relatively high transmissibility appear to be rapidly spreading in Gabon. Therefore, it is imperative to understand the distribution of several VOCs in the population, which could have implications for transmissibility and vaccine efficacy., Methods: Between February and May 2021, SARS-CoV-2 genomes were sequenced using the Oxford nanopore MinION method and the respective genome diversity was elucidated. Phylogenetic analysis was performed and genomes were classified using pangolin lineages., Results: The results highlighted an increase (46%) in the alpha VOC (B.1.1.7) in the Gabonese population over the study period. In addition, an increase (31%) in the B.1.1.318 lineage, which is associated with high transmission and impaired vaccine efficacy (D614G+E484K+Y144del), was detected., Conclusion: With the second wave ongoing, these findings highlight the need for surveillance of the SARS-CoV-2 genome in the Republic of Gabon and should provide useful guidance to policymakers in selecting an appropriate vaccine for this population., Competing Interests: Conflicts of interest The authors declare no conflict of interest in the submitted work., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

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., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Purpose: Since May 2016, WHO recommended a 9-12 month short-treatment regimen for multidrug-resistant tuberculosis (MDR-TB) treatment known as the 'Bangladesh Regimen'. However, limited data exist on the appropriateness thereof, and its implementation in low- and middle-income countries (LMIC). We report here on the pilot phase of the evaluation of the Bangladesh regimen in Gabon, prior to its endorsement by the WHO., Methods: This ongoing observational study started in September 2015. Intensive training of hospital health workers as well as community information and education were conducted. GeneXpert-confirmed MDR-TB patients received the second-line anti-tuberculosis drugs (4KmMfxPtoHCfzEZ/5MfxCfzEZ). Sputum smears and cultures were done monthly. Adverse events were monitored daily., Results: Eleven patients have been treated for MDR-TB piloting the short regimen. All were HIV-negative and presented in poor health with extensive pulmonary lesions. The overall sputum culture conversion rate was 64% after 4 months of treatment. Three patients developed marked hearing loss; one a transient cutaneous rash. Of 11 patients in our continuous care, 7 (63.6%) significantly improved clinically and bacteriologically. One (9.1%) patient experienced a treatment failure, two (18.2%) died, and one (9.1%) was lost to follow up., Conclusions: Our pioneering data on systematic MDR-TB treatment in Gabon, with currently almost total absence of resistance against the second-line drugs, demonstrate that a 9-month regimen has the capacity to facilitate early culture negativity and sustained clinical improvement. Close adverse events monitoring and continuous care are vital to success.

Background: HIV infection is accompanied by various systemic host responses, including activation of coagulation and the vascular endothelium. We sought to determine the impact of opportunistic coinfections in a central African setting., Methods: This prospective study included 98 HIV-infected individuals in Gabon initiating combination antiretroviral therapy (cART) and followed them up for 6 months. Patients were stratified according to the presence of active tuberculosis (TB; n=19), mucocutaneous opportunistic infection (n=9) or no opportunistic infection (n=70). HIV-uninfected subjects were included as controls (n=32). Plasma concentrations of 14 markers of coagulation, endothelial activation, extracellular matrix formation and tissue damage were measured with a multiplex assay at baseline and months 3 and 6 after cART initiation., Results: HIV-infected patients showed elevated plasma levels of all biomarkers measured with exception of protein C, which was reduced. Concurrent TB was only associated with elevated concentrations of D-dimer, metallopeptidase inhibitor 1 and Tenascin-C. Mucocutaneous coinfection did not alter HIV-associated responses. Most markers measured declined but remained elevated despite response to cART., Conclusions: HIV infection is associated with systemic pro-coagulant, vascular and damage responses. In an ambulatory setting, concurrent opportunistic infections have little if any influence on these responses and normalization is incomplete after response to cART. This suggests that these responses are mainly driven by HIV-associated immune activation and less so by opportunistic infections.

Despite overall global progress in tuberculosis (TB) control, TB remains one of the deadliest communicable diseases. This study prospectively assessed TB epidemiology in Lambaréné, Gabon, a Central African country ranking 10th in terms of TB incidence rate in the 2014 World Health Organization TB report. In Lambaréné, between 2012 and 2014, 201 adult and pediatric TB patients were enrolled and followed up; 66% had bacteriologically confirmed TB and 95% had pulmonary TB. The human immunodeficiency virus (HIV) coinfection rate was 42% in adults and 16% in children. Mycobacterium tuberculosis and Mycobacterium africanum were identified in 82% and 16% of 108 culture-confirmed TB cases, respectively. Isoniazid (INH) and streptomycin yielded the highest resistance rates (13% and 12%, respectively). The multidrug resistant TB (MDR-TB) rate was 4/91 (4%) and 4/13 (31%) in new and retreatment TB cases, respectively. Treatment success was achieved in 53% of patients. In TB/HIV coinfected patients, mortality rate was 25%. In this setting, TB epidemiology is characterized by a high rate of TB/HIV coinfection and low treatment success rates. MDR-TB is a major public health concern; the need to step-up in-country diagnostic capacity for culture and drug susceptibility testing as well as access to second-line TB drugs urgently requires action., (© The American Society of Tropical Medicine and Hygiene.)

Background: Retention to HIV care is vital for patients' survival, to prevent onward transmission and emergence of drug resistance. Travelling to receive care might influence adherence. Data on the functioning of and retention to HIV care in the Central African region are limited., Methods: This retrospective study reports outcomes and factors associated with retention to HIV care at a primary HIV clinic in Lambaréné, Gabon. Adult patients who presented to this clinic between January 2010 and January 2012 were included. Outcomes were retention in care (defined as documented show-up for clinical visits, regardless of delay) or LTFU (defined as a patient not retained in care; on ART or ART naïve, not returning to care during the study period with a patient delay for scheduled visits of more than 6 months), and mortality. Cox regression analysis was used to assess factors associated with respective outcomes. Qualitative data on reasons for LTFU were obtained from focus-group discussions., Results: Of 223 patients included, 67.3% were female. The mean age was 40.5 (standard deviation 11.4) years and the median CD4 count 275 (interquartile range 100.5-449.5) cells/μL. In total, 34.1% were lost to follow up and 8.1% died. Documented tuberculosis was associated with increased risk of being LTFU (adjusted hazard ratio (aHR) 1.80, 95% confidence interval (95% CI) 1.05-3.11, P = 0.03), whereas early starting anti-retroviral therapy (ART) was associated with a decreased risk of LTFU (aHR 0.43, 95%CI 0.24-0.76, P = 0.004), as was confirmed by qualitative data., Conclusions: Retention to HIV care in a primary clinic in Gabon is relatively poor and interventions to address this should be prioritized in the HIV program. Early initiation of ART might improve retention in care.

Background: Foci of the HIV epidemic and helminthic infections largely overlap geographically. Treatment options for helminth infections are limited, and there is a paucity of drug-development research in this area. Limited evidence suggests that antiretroviral therapy (ART) reduces prevalence of helminth infections in HIV-infected individuals. We investigated whether ART exposure and cotrimoxazole preventive therapy (CTX-P) is associated with a reduced prevalence of helminth infections., Methodology and Principal Findings: This cross-sectional study was conducted at a primary HIV-clinic in Lambaréné, Gabon. HIV-infected adults who were ART-naïve or exposed to ART for at least 3 months submitted one blood sample and stool and urine samples on 3 consecutive days. Outcome was helminth infection with intestinal helminths, Schistosoma haematobium, Loa loa or Mansonella perstans. Multivariable logistic regression was used to assess associations between ART or CTX-P and helminth infection. In total, 408 patients were enrolled. Helminth infection was common (77/252 [30.5%]). Filarial infections were most prevalent (55/310 [17.7%]), followed by infection with intestinal helminths (35/296 [11.8%]) and S. haematobium (19/323 [5.9%]). Patients on CTX-P had a reduced risk of Loa loa microfilaremia (adjusted odds ratio (aOR) 0.47, 95% CI 0.23-0.97, P = 0.04), also in the subgroup of patients on ART (aOR 0.36, 95% CI 0.13-0.96, P = 0.04). There was no effect of ART exposure on helminth infection prevalence., Conclusions/significance: CTX-P use was associated with a decreased risk of Loa loa infection, suggesting an anthelminthic effect of antifolate drugs. No relation between ART use and helminth infections was established.

Patients infected with the human immunodeficiency virus (HIV) are frequently exposed to antimicrobial agents. This might have an impact on the resistance profile, genetic background and virulence factors of colonizing Staphylococcus aureus. Sub-Saharan Africa is considered to be endemic for Panton-Valentine leukocidin (PVL) positive S. aureus which can be associated with skin and soft tissue infections (SSTI). We compared S. aureus from nasal and pharyngeal swabs from HIV patients (n = 141) and healthy controls (n = 206) in Gabon in 2013, and analyzed determinants of colonization with PVL positive isolates in a cross-sectional study. S. aureus isolates were screened for the presence of selected virulence factors (incl. PVL) and were subjected to antimicrobial susceptibility testing and genotyping. In HIV patients, S. aureus was more frequently detected (36.9 vs. 31.6%) and the isolates were more frequently PVL positive than in healthy controls (42.1 vs. 23.2%). The presence of PVL was associated with cotrimoxazole resistance (OR = 25.1, p < 0.001) and the use of cotrimoxazole was a risk factor for colonization with PVL positive isolates (OR = 2.5, p = 0.06). PVL positive isolates were associated with the multilocus sequence types ST15 (OR = 5.6, p < 0.001) and ST152 (OR = 62.1, p < 0.001). Participants colonized with PVL positive isolates reported more frequently SSTI in the past compared to carriers of PVL negative isolates (OR = 2.7, p = 0.01). In conclusion, the novelty of our study is that cotrimoxazole might increase the risk of SSTI in regions where cotrimoxazole resistance is high and associated with PVL. This finding needs to be confirmed in prospective studies.

We report the case of a Gabonese HIV-patient who presented with haemoptysis, weight loss, fulminant diarrhoea and subsequent ileus and elevated CD4+ T-cell counts. He was diagnosed with Strongyloides stercoralis and human T-lymphotrophic virus type-1 infection. After treatment of the strongyloides hyperinfection syndrome, his CD4+ T-cell counts dropped greatly. The initially elevated CD4+ T-cell counts were misleading to the clinicians with regard to decision-making on antiretroviral therapy initiation.