Culex Pipiens (Diptera: Culicidae) Morbidity and Mortality Associated with Rift Valley Fever Virus Infection22

Abstract

Experiments were conducted to determine whether infection with Rift Valley fever (RVF) virus resulted in increased morbidity or mortality in infected Egyptian Culex pipiens. Following oral exposure to RVF virus, mosquitoes with disseminated infections showed a 21% reduction in refeeding rate and a 20% reduction in the number of eggs laid compared to uninfected mosquitoes. Mosquitoes with nondisseminated infections had refeeding and egg-laying rates intermediate between those for uninfected and disseminated individuals. All larvae inoculated with RVF virus failed to emerge successfully as adults. However, no increased mortality was observed for larvae inoculated with La Crosse virus compared to those inoculated with diluent. The increased morbidity observed for RVF-virus-infected Cx. pipiens may need to be incorporated in models of the natural history of this virus.