Vector Competence of Florida (Diptera: Ceratopogonidae) for Epizootic Hemorrhagic Disease Virus Serotype-2.

Epizootic hemorrhagic disease virus (EHDV; family , genus ) is an arthropod-borne virus of ungulates, primarily white-tailed deer in North America. , the only confirmed North American vector of EHDV, is rarely collected from Florida despite annual virus outbreaks. is an abundant species in Florida and is also a confirmed vector of the closely related Bluetongue virus. In this study, oral challenge of was performed to determine vector competence for EHDV serotype-2. Field-collected female midges were provided bovine blood spiked with three different titers of EHDV-2 (5.05, 4.00, or 2.94 logPFUe/mL). After an incubation period of 10 days or after death, bodies and legs were collected. Saliva was collected daily from all females from 3 days post feeding until their death using honey card assays. All samples were tested for EHDV RNA using RT-qPCR. Our results suggest that is a weakly competent vector of EHDV-2 that can support a transmissible infection when it ingests a high virus titer (29% of midges had virus positive saliva when infected at 5.05 logPFUe/mL), but not lower virus titers. Nevertheless, due to the high density of this species, particularly in peninsular Florida, it is likely that plays a role in the transmission of EHDV-2.