1. Wyoming Game and Fish Department, 2362 Highway 34, Wheatland, Wyoming 82201, USA
2. USDA/APHIS/WS, National Wildlife Research Center, Utah State University, Logan, Utah 84322, USA
3. Zoonotic Disease Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, 2300 Dayton Ave., Ames, Iowa 50010, USA
4. Wyoming Game and Fish Department, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA