Genetic Diversity and Detection of Respiratory Viruses Excluding SARS-CoV-2 during the COVID-19 Pandemic in Gabon, 2020-2021.

Acute respiratory infections are a major global burden in resource-limited countries, including countries in Africa. Although COVID-19 has been well studied since the pandemic emerged in Gabon, Central Africa, less attention has been paid to other respiratory viral diseases, and very little data are available. Herein, we provide the first data on the genetic diversity and detection of 18 major respiratory viruses in Gabon during the COVID-19 pandemic. Of 582 nasopharyngeal swab specimens collected from March 2020 to July 2021, which were SARS-CoV-2 negative, 156 were positive (26%) for the following viruses: enterovirus (20.3%), human rhinovirus (HRV) (4.6%), human coronavirus OC43 (1.2%), human adenovirus (0.9%), human metapneumovirus (hMPV) (0.5%), influenza A virus (IAV) (0.3%), and human parainfluenza viruses (0.5%). To determine the genetic diversity and transmission route of the viruses, phylogenetic analyses were performed using genome sequences of the detected viruses. The IAV strain detected in this study was genetically similar to strains isolated in the USA, whereas the hMPV strain belonging to the A2b subtype formed a cluster with Kenyan strains. This study provides the first complete genomic sequences of HRV, IAV, and hMPV detected in Gabon, and provides insight into the circulation of respiratory viruses in the country.

Distribution of Aedes mosquito species along the rural-urban gradient in Lambaréné and its surrounding.

BACKGROUND: Aedes albopictus and Aedes aegypti are known for their potential as vectors of dengue (DENV) and chikungunya (CHIKV) viruses. However, entomological surveys are mostly carried out during epidemics. In Gabon where outbreaks of both viruses have occurred, there is no vector control program targeting these arboviruses. Therefore, we assessed the presence of Aedes species along a rural-urban gradient in Lambaréné (Gabon) and its surroundings and determined ecological factors associated to their presence. METHODS: An entomological survey was conducted in Lambaréné and its surrounding rural areas. Mosquitoes were collected with aspirators around human dwellings, and ecological and environmental data were collected from each study area. Morphological identification keys were used to identify Aedes species. RNA was extracted from pools of female mosquitoes and amplified by RT-qPCR to detect the presence of DENV and CHIKV. RESULTS: Overall, the most common vector collected was Aedes albopictus (97%, 4236/4367 specimens), followed by Aedes aegypti (3%, 131/4367). Albopictus vectors was more abundant in the rural area (Wilcoxon signed-rank test, Z = 627, P = 0.043) than in the urban area. In the urban area, a higher number of mosquitoes (45%) were recorded in the economic zone (zone 3) than in the historical and administrative zones (zone 1 and 2). In the rural area, the proportions of species numbers were significantly higher along the south rural transect (92%) compared to the north rural transect (Wilcoxon signed-rank test, Z = 43, P ˂ 0.016). We also noted a high abundance of vectors in environments characterized by monocultures of Hevea brasiliensis (Hevea) and Manihot esculenta (cassava) (Kruskal-Wallis H-test, H = 25.7, df = 2, P < 0.001). Finally, no mosquito pools were positive for either DENV or CHIKV. CONCLUSION: Aedes albopictus was the dominant vector across the study sites due to its high invasiveness capacity. This presence re-affirms the potential for local transmission of both DENV and CHIKV, as indicated previously by serological surveys conducted in our study area, even though no transmission was detected during the current study. These findings underscore the need for regular arbovirus surveillance in the study region, with the aim of supporting vector control efforts in the event of outbreaks.

Knowledge, attitudes and practices pertaining to urogenital schistosomiasis in Lambaréné and surrounding areas, Gabon.

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.