Vector competence tests with Rift Valley fever virus and five South African species of mosquito.

Aedes juppi was readily infected by inoculation with virus but failed to transmit either horizontally or vertically. Seventy-five to 90% of the other 4 mosquito species became infected after ingesting 6.8-9.8 log10CPD50/ml of virus. These species all transmitted virus at the following rates on the post-infection days indicated: Aedes unidentatus (58%--day 11), Aedes dentatus (32%--day 11, 50%--day 18), Culex poicilipes (15%--day 15, 80%--day 30) and Aedes argenteopunctatus (14% on day 30). On the basis of these results and the relative prevalence of each species, it was concluded that Ae. unidentatus and Ae. dentatus are potential epizootic and possibly reservoir vectors and Cx. poicilipes a potential epizootic vector of Rift Valley fever virus in South Africa.