Observations on epizootiology and distribution of Elaeophora schneideri in Montana ruminants

Seventy-four moose, 111 elk, 20 mule deer, 8 white-tailed deer, 26 prong-horn antelope, 42 domestic sheep and 3 bighorn sheep from Montana or northwestern Wyoming were examined post-mortem for evidence of Elaeophora schneideri infection in 1973-74. Fifteen percent of the mule deer and four percent of the moose were positive for adult arterial worms. This constitutes the first report of E. schneideri in mule deer in Montana. No gross signs of blindness or other neurologic disorder were evident in the infected animals. Potential horsefly intermediate hosts collected in the enzootic area included Hybomitra rhombica osburni, H. tetrica, H. metabola, Chrysops noctifer pertinax and Atylotus incisuralis.