Experimental Evaluation of Musca domestica (Diptera: Muscidae) as a Vector of Newcastle Disease Virus

Watson, D. Wes; Niño, Elina L.; Rochon, Kateryn; Denning, Steve; Smith, Lynda; Guy, James S.

In summary, after a single feeding, the house ßy harbored live NDV Roakin in both crop and gut tissues 96 and 24 h, respectively. NDV did not replicate in ßy crop or digestive tract tissues. Mechanical transmission of NDV by the house ßy was not demonstrated in the current study. In controlled experiments, NDVexposed house ßies did not transmit NDV even though each ßy carried Ϸ10 4 ID 50 of virus when placed in contact with susceptible chickens. This was unexpected, because NDV-exposed ßies were eaten by contact chickens soon after placement in isolation units. However, subsequent experiments demonstrated a dose effect for NDV Roakin: an ID 50 Ն10 6 was required to infect chickens by the oral route, the likely route of transmission for NDV by ßies. These studies indicate that at least for NDV Roakin, house ßies did not carry sufÞcient quantities of virus to infect chickens and are unlikely vectors. Additional studies using other NDV strains, particularly velogenic strains, are needed to deÞnitively determine the role of house ßies as vectors of NDV.