Mortality of Culicoides brevitarsis (Diptera: Ceratopogonidae) Fed on Cattle Treated with Ivermectin

Abstract

Adult Culicoides brevitarsis Kieffer, an important vector of arboviruses affecting livestock in Australia, were fed on cattle which had been subcutaneously injected with ivermectin, a systemic insecticide, at a dose of 200 µg/kg. The mean mortality of engorged insects 48 h after feeding was 99% for 10 days post treatment, whereas in one animal it exceeded 47% for 24 days. The results of the study indicate that ivermectin administered subcutaneously could be a useful tool for the control of outbreaks of Culicoides-transmitted disease, and would provide an attractive alternative to “slaughter out” programs in the case of a major exotic disease threat.