Epidemiology of western encephalitis in Alberta: response of natural populations of mosquitoes to avian host.

Abstract

The response of natural populations of mosquitoes to avian host was determined under field conditions in dryland and irrigated areas in Alberta. Caged flocks of chickens were used as avian host. Females of Culex tarsalis, Culiseta inornata, Aedes flavescens, Aedes dorsalis, Aedes spencerii, Aedes vexaus, Aedes campestris, Aedes cataphylla , and Aedes nigromaculis were attracted to and readily fed on the chickens although other hosts were available in the areas studied. Bird-biting mosquitoes, which are in continuous supply throughout the spring and summer, were observed to feed on nestlings of Franklin gulls, red-winged blackbirds, Brewer's blackbirds, yellow-headed blackbirds, and ringed-neck pheasants. The interrelations of mosquito and bird populations are believed to be essential factors in the epidemiology of Western Encephalitis virus in the study area.