Vector competence of peruvian mosquitoes (Diptera : culicidae) for epizootic and enzootic strains of Venezuelan equine encephalomyelitis virus

Mosquitoes collected in the Amazon Basin, near Iquitos, Peru, were evaluate d for their susceptibility to epizootic (IAB and IC) and enzootic (ID and I E) strains of Venezuelan equine encephalomyelitis (VEE) virus. After feedin g on hamsters with a viremia of approximate to 10(8) plaque-forming units o f virus per milliliter, Culex (Melanoconion) gnomatus Sallum, Huchings, & F erreira, Culex (Melanoconion) vomerifer Komp, and Aedes fulvus (Wiedemann) were highly susceptible to infection with all four subtypes of VEE virus (i nfection rates greater than or equal to 87%). Likewise, Psorophora albigenu (Peryassu) and a combination of Mansonia indubitans Dyar & Shannon and Man sonia titillans (Walker) were moderately susceptible to all four strains of VEE virus (infection rates greater than or equal to 50%). Although Psoroph ora cingulata (Fabricius) and Coquillettidia venezuelensis (Theobald) were susceptible to infection with each of the VEE strains, these two species we re not efficient transmitters of any of the VEE strains, even after intrath oracic inoculation, indicating the presence of a salivary gland barrier in these species. In contrast to the other species tested, both Culex (Melanoc onion) pedroi Sirivanakarn & Belkin and Culex (Culex) coronator Dyar & Knab were nearly refractory to each of the strains of VEE virus tested. Althoug h many of the mosquito species found in this region were competent laborato ry vectors of VEE virus, additional studies on biting behavior, mosquito po pulation densities, and vertebrate reservoir hosts of VEE virus are needed to incriminate the principal vector species.