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.

Experiment 1. Adult house ßies harbored Newcastle Disease virus in both crop and gut tissues. Live NDV was detected in crops tissues of house ßies for 96 h postfeeding in two of three replicated experiments (Table 1 ). In the one replicate, NDV was detectable at 24 h postexposure, but not at 96 h. Virus titers were greatest within 30 min of a single feeding of the ßies. NDV titer decay was predictably time dependent from 0.5 to 24 h following the logistic model [y ϭ Ϫ0.4306ln(x) ϩ 2.0187; R 2 ϭ 0.7329] (Fig. 1) . Virus titers would be expected to remain stable or increase if NDV survived or was replicated in the ßy tissues. NDV was not detected in the tissues of shamexposed ßies collected at the same time intervals. Experiment 2. NDV was detected in the gut tissues of the house ßy for 24 h postfeeding (Table 2 .) Titration of NDV in gut tissues at the 30-min interval was greater than that found in the crop tissues. The 24-h rate of decay in virus titer was time dependent in the gut tissues [y ϭ Ϫ1.2677ln(x) ϩ 4.3786; R 2 ϭ 0.914] (Fig. 1) . Little virus as detected 9 h after the initial exposure to NDV. Virus was not detected in the tissues of sham-exposed ßies collected at the same time intervals.