Experimental infection of Culicoides lahillei (Diptera: Ceratopogonidae) with epizootic hemorrhagic disease virus serotype 2 (Orbivirus: Reoviridae).

To evaluate the vector competence of Culicoides lahillei Lutz for epizootic hemorrhagic disease (EHD) viruses, wild-caught females were allowed to feed on 4 viremic white-tailed deer, Odocoileus virginianus Zimmermann, experimentally infected with EHD virus serotype 2 (EHDV-2). Colonized C. variipennis sonorensis (Coquillett) were included as a positive control. Virus was not isolated from 13 C. lahillei tested 4-15 d after feeding on deer with viremias of 3.0 or <2.1 log10 tissue culture infectious dose50 (TCID50) virus per milliliter of blood. Virus was isolated from 6 of 69 (8.7%) C. lahillei tested 4-15 d after feeding on deer with viremias of 5.3 or 6.0 TCID50 virus per milliliter of blood. The average amount of EHDV-2 ingested in the blood meal ranged from <log10 1.5 to log10 1.9 TCID50 per C. lahillei. Titers of EHDV-2 in C. lahillei that tested positive 4-15 d after feeding peaked at log10 2.7 TCID50 EHDV per fly. Replication of EHDV-2 also occurred in control C. variipennis. This report of infection of C. lahillei with an EHD virus serotype indicates that C. lahillei may be a vector of EHD viruses.