1. Department of Microbiology, Immunology, and Pathology, Colorado State University, 3107 Rampart Road, Fort Collins, Colorado 80523, USA
2. Australian Infectious Diseases Research Centre, University of Queensland, St. Lucia, Gatton, QLD 4343, Queensland, Australia
3. Wildlife Services, Animal and Plant Health Inspection Service, US Department of Agriculture, 755 Parfet Street, Lakewood, Colorado 80228, USA
4. Department of Clinical Sciences, Colorado State University, 300 W Drake Road, Fort Collins, Colorado 80525, USA