Ecology of mosquitoes vectors associated with eastern equine encephalitis in Georgia

Eastern Equine Encephalitis virus (EEEV) is a single-stranded RNA arbovirus (family Togaviridae; genus Alphavirus) endemic to the Atlantic seaboard and southeastern United States. EEEV produces particularly severe disease in incidental hosts such as humans and horses, with case fatality rates in symptomatic humans and horses typically exceeding 70%. Although outbreaks of EEEV in humans and horses are sporadic in nature, the virulence and high costs associated with the virus makes EEEV of particular concern. The basic transmission cycle of EEEV is well understood: the virus is maintained enzootically by an avian-mosquito transmission cycle, with other vertebrates serving as incidental hosts. The primary mosquito vector (Culiseta melanura) is highly ornithophilic and cannot maintain viral infectivity through winter. Other mosquitoes with more catholic feeding behaviors (e.g., Coquillettidia perturbans) are responsible for transmission of EEEV to non-avian vertebrates. EEEV has been shown to not be maintained in overwintering mosquitoes.  During winter infected avians clear EEEV infections from the blood. However, each spring the virus reemerges. Other vertebrates, potentially including long-lived reptiles, must serve as the overwintering host for EEEV, but as of yet exactly which vertebrates occupy this pivotal role in transmission remains unknown. This study attempts to profile the relative abundance and feeding behavior of potential bridge vectors collected in association with documented cases of EEEV in Georgia, and in doing so identify potential overwintering hosts of EEEV.