Biting Midge Harbors Livestock Disease Virus

VSV causes significant economic losses to the livestock industry from sickened animals, quarantines and subsequent export/import restrictions.

Drolet, at the ARS Arthropod-Borne Animal Diseases Research Laboratory in Laramie, Wyo., and colleagues now have proof that VSV is capable of surviving and spreading throughout the blood-sucking midge, Culicoides sonorensis. To verify that Culicoides propagated VSV, the scientists had to find a way to show, without killing the midge, that virus ingested in a blood meal could survive the insect's midgut, then replicate and escape from the midgut to infect other organs.

Using an artificial feeding system, Drolet fed midges a viral meal and tracked the ensuing infections over time to show that VSV infects the midge's salivary glands and eggs and is shed in the midge's droppings. Drolet used a genetic technique to verify that the virus is able to replicate within the insect.