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.

The house ßy satisÞes many requirements of an efÞcient vector: abundance, mobility, tendency to feed on manure, and ability to harbor pathogenic agents. The current study demonstrates the potential of the house ßy to harbor NDV in the crop and gut tissues, and it conÞrms the Þndings of Milushev et al. (1977) . Virus was detectible in the ßy crop for 96 h after a single feeding event. Virus titers in pooled ßy crops ranged from 10 3 ID 50 measured within 30 min of feeding on NDV inoculum to Ͻ10 1 ID 50 at 96 h. Although NDV titers in pooled mid-and hindgut tissues were higher (10 7 ID 50 /0.2 ml) immediately after a single feeding, live virus was only detectable for 24 h. The starting NDV dose was Ϸ10 7 ID 50 for both experiment 1 and 2. It is interesting that the crop had much less virus at 30 min than the gut, suggesting that the ßies directed a signiÞcant portion of the virus containing medium directly to the gut in response to periods of food deprivation. In a previous study, we found turkey coronavirus (family Coronaviridae, genus Coronavirus, TCV) remained active in the crop of a NDV was not detected in the tissues of sham-exposed ßies collected at the same time intervals.