1. Bacterial Disease Branch, Division of Vector-Borne Disease, Centers for Disease Control and Prevention, 3156 Rampart Rd., Fort Collins, Colorado 80521, USA
2. National Wildlife Research Center, USDA/APHIS/Wildlife Services, 4101 Laporte Ave., Fort Collins, Colorado 80521, USA
3. Colorado Parks and Wildlife, 317 W Prospect Rd., Fort Collins, Colorado 80525, USA