The multiplication of African horse-sickness virus in two species of Culicoides (Diptera, Ceratopogonidae).

Type 9 African horse-sickness virus multiplied to a high titre in both Culicoides nubeculosus and C. variipennis after intrathoracic inoculation and in C. variipennis after oral ingestion. The orally infected C. variipennis were able to transmit the virus by biting after 13 days incubation at 26 degrees C but not after 6 days incubation. Intrathoracically inoculated C. variipennis were able to transmit the virus after 4 days incubation. It is suggested that C. variipennis can act as a biological vector of African horse-sickness virus.