1. Department of Epidemiology and Preventive Medicine, School of Veterinary Medicine, University of California, Davis, California 95616, USA
2. International Wildlife Veterinary Services, P.O. Box 1413, Orangevale, California 95662, USA
3. California Department of Fish and Game, 1701 Nimbus Road, Rancho Cordova, California 95670, USA
4. University of California White Mountain Research Station, Bishop, California 93514, USA