1. Colorado State Diagnostic Laboratory, College of Veterinary Medicine, Colorado State University, Fort Collins, Colorado 80523, USA
2. Colorado Division of Wildlife, 317 West Prospect Road, Fort Collins, Colorado 80526, USA
3. Department of Veterinary Sciences, University of Wyoming, 1174 Snowy Range Road, University of Wyoming, Laramie, Wyoming 82070, USA
4. USDA-ARS, 337 Bustad, Washington State University, Pullman, Washington 99164, USA
5. USDA-ARS, National Animal Disease Center, Box 70, Ames, Iowa 50010, USA
6. New York State Institute for Basic Research, 1050 Forest Hill Road, Staten Island, New York 10314, USA