Detection of DENV-1, DENV-3 and DENV-4 serotypes in Ae. aegypti and Ae. albopictus, and epidemic risk in the departments of Oueme and Plateau, South-Eastern Benin

Abstract

Abstract Background The present study conducted in the departments of Oueme and Plateau, aims to assess the presence of the dengue virus and its different serotypes in Ae. aegypti and Ae. albopictus, as well as the epidemic risk incurred by the populations.Method Collections of adult mosquitoes using human landing catches (HLC) were carried out in six communes, three of which (Porto-Novo, Adjarra and Avrankou) in the Oueme department, and the rest (Ifangni, Kétou and Pobè) in the Plateau department. Pools of ten Aedes mosquitoes were formed, and stored at − 80°C in RNA later. RT-PCR was used to detect dengue virus, and conventional PCR for the different setotypes. Inspection of water containers and collection of Aedes larvae were performed inside and around each house in order to calculate the stegomyan indices.Results In the six communes studied, the dengue virus was present both in Ae. Aegypti, and Ae. albopictus. Combined data of the two Aedes species at the communes level, revealed infection rates ranging from 80.00% (95% CI: 61.43–92.29) to 96.67% (95% CI: 82.78–99.92). In addition, the infection rates were similar for Aedes aegypti [88.19% (95% CI: 81.27–93.24)] and Aedes albopictus 86.79% [(95% CI: 74.66–94.52)]. The three virus serotypes detected in the pools of Aedes were: DENV-1, DENV-3 and DENV-4, with a high prevalence for the first two. Whatever the communes, the values of the stegomyan indices reached the threshold that indicates the existence of the risk of an arbovirosis epidemic.Conclusion The present study revealed that three serotypes (DENV-1, DENV-3 and DENV-4) of dengue virus circulate in Aedes aegypti and Aedes albopictus in the departments of Oueme and Plateau. Moreover, the risk of transmission of arboviruses was globally high and variable from commune to commune. These information are essential for informed decision-making in the preventive control of the disease.