Avian host preference by vectors of eastern equine encephalomyelitis virus.

An important variable in the amplification and escape from the enzootic cycle of the arboviral encephalitides is the degree of contact between avian hosts and mosquito vectors. To analyze this interaction in detail, blood-fed mosquitoes that were confirmed vectors of eastern equine encephalomyelitis (EEE) virus were collected in 2002 from an enzootic site in central Alabama during the time this virus was actively transmitted. Avian-derived blood meals were identified to the species level of the host, and the proportion derived from each species was compared with the overall composition of the avifauna at the study site. The EEE vector mosquito species fed significantly more on some bird species and less on other species than expected given the overall abundance, biomass, or surface area of the local avifauna. When viewed collectively, these data suggest that these mosquitoes are selectively targeting particular avian species.