Diversité et répartition spatio-temporelle des Aedes et détection du virus de la dengue chez ces moustiques à l’université de Yaoundé 1 et ses environs

Abstract

The mosquitoes of the genus Aedes constitute a major public health problem in sub- Saharan Africa because they are involved in the transmission of several diseases such as dengue, yellow fever, chikungunya, Zika, etc., to humans. To effectively combat these diseases, knowledge of the diversity and distribution of Aedes species involved in their transmission is a prerequisite. Moreover, the early detection of these arboviruses in hosts (mosquitoes and humans) would prompt decision-makers to take rapid measures to prevent epidemics. Thus, the objective of this study was to determine the diversity and spatio-temporal distribution of Aedes mosquitoes and also to detect the dengue virus in these female mosquitoes on the campus of the University of Yaoundé 1 (UY1) and its surroundings. Aedes larvae and adults were sampled at 4 sites located in and around the UY1 campus. Larval specimens were reared in the laboratory until adult emergence. Emerged adults and those captured in the field were identified using the morphological dichotomous keys for Aedes identification established by Robert et al., 2022 ; Edwards, 1941 ; and Jupp, 1996. Detection of the dengue virus in female Aedes was performed using the dengue NS1 antigen rapid diagnostic test. In total, 1023 Aedes mosquitoes were sampled on the UY1 campus and its surroundings during 6 months of sampling. After identification, 8 (eight) species were recorded, namely Aedes albopictus (65,00%), Ae. aegypti (21,90%), Ae. vexans (7,20%), Ae. fowleri (2,30%), Ae. Africanus (1,80%), Ae. dentatus (1,50%), Ae. japonicus (0,20%), and Ae. sp. (0,10%). Species diversity varied over time and space; the Obili neighborhood (5 species) was the area with the highest Aedes species diversity, and the month of april had the greatest number of species (5 species). Ae. albopictus was the most dominant species in all sites and during all months of the study, except in the Melen neighborhood where it was absent. Tires were identified as the most productive breeding sites for Aedes, with Ae. albopictus dominating these habitats. Among the 50 Aedes specimens tested, only one female mosquito carried the dengue virus. Thus, the student environment of UY1 is diverse in Aedes species, vectors of arboviruses, and likely contributes actively to the circulation of the dengue virus in the city of Yaoundé in general and around the UY1 campus in particular.