Studies on Onchocerca cervicalis Railliet and Henry 1910: V. The development of Onchocerca cervicalis larvae in the vectors.

Colonies of Culicoides nubeculosus and C; variipennis were established at Winches Farm Field Station, St. Abans. Both species of midge were found to be susceptible to infection with Onchocerca cervicalis microfilariae. Infection was achieved either by engorging through a chick skin membrane on a suspension of microfilariae in blood, or by feeding upon a horse naturally infected with O. cervicalis microfilariae. A large proportion of the microfilariae ingested by the midges penetrated into the haemocoel and migrated first to the thoracic flight muscles and then to the head. Larval development occurred during migration and 3rd stage (infective) larvae of O. cervicalis reached the head of infected midges (kept at 23 degrees C.) 14-15 days after engorgement.