Infection and dissemination of Venezuelan equine encephalitis virus in the epidemic mosquito vector, Aedes taeniorhynchus.
The mosquito Aedes taeniorhynchus is an important epidemic vector of Venezuelan equine encephalitis virus (VEEV), but detailed studies of its infection are lacking. We compared infection by an epidemic VEEV strain to that by an enzootic strain using virus titrations, immunohistochemistry, and a virus expressing the green fluorescent protein. Ae. taeniorhynchus was more susceptible to the epidemic strain, which initially infected the posterior midgut and occasionally the anterior midgut and cardia. Once dissemination beyond the midgut occurred, virus was present in nearly all tissues. Transmission of the epidemic strain to mice was first detected 4 days after infection. In contrast, the enzootic strain did not efficiently infect midgut cells but replicated in muscles and nervous tissue on dissemination. Because VEEV emergence can depend on adaptation to epidemic vectors, these results show that epidemic/enzootic strain comparisons not only comprise a useful model system to study alphavirus transmission by mosquitoes, but also have important public health implications.
Smith
Darci R
DR
Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Histopathology Service Core, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA. darci.smith@amedd.army.mil
Arrigo
Nicole C
NC
Leal
Grace
G
Muehlberger
Linda E
LE
Weaver
Scott C
SC
D000330:Aedes / Q000821:virology*; D000818:Animals; D004666:Encephalitis Virus, Venezuelan Equine / Q000472:pathogenicity*; D004685:Encephalomyelitis, Venezuelan Equine / Q000453:epidemiology / Q000209:etiology / Q000635:transmission*; D006801:Humans; D007150:Immunohistochemistry; D007303:Insect Vectors / Q000821:virology*; D013781:Texas / Q000453:epidemiology