1. Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, 1126 Haring Hall, 1 Shields Avenue, University of California, Davis, California 95616, USA
2. Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, California 95616, USA
3. Department of Zoology, Michigan State University, East Lansing, Michigan 48824, USA
4. Animal Health Diagnostic Laboratory, College of Veterinary Medicine, Cornell University, Ithaca, New York 14852, USA
5. Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine, Colorado State University, Fort Collins, Colorado 80523, USA