Studies on the vector competence of a Mid-western strain of Aedes vexans (Meigen) (Diptera: Culicidae) for West Nile Virus

Abstract

Aedes vexans (Meigen) mosquitoes were given access to 2to 4-day-old chickens inoculated with 10 CID50s / ml West Nile Virus (WNV) at 1 day old. Mosquitoes were given access to chickens at different intervals after inoculation to make certain that blood meals from chickens were of varying virus titers. No differences occurred in infection rates of Ae. vexans and Culex pipiens (L.) fed on the same WNV viremic chicken. Infection rates of Ae. vexans were higher (79%) when fed on chickens with viremias of 6.0 log10 WNV PFUs / ml or higher than they were (27%) in mosquitoes fed on chickens with viremias below 6.0 log10 WNV PFUs / ml. Dissemination rates were similar in Ae. vexans 14 and 21 days post blood feeding (PBF) (74 % and 74 %, respectively) . Likewise, transmission rates were similar in Ae. vexans 14 days and 21 days PBF (25 % and 27 %, respectively). Aedes vexans fed on viremic chickens became infected, developed disseminated infections, ________________ Department of Entomology, Iowa State University, Ames, IA 50011 USA Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA 50011 USA Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA 50011 USA