1. Pathobiology Laboratory, National Veterinary Services Laboratories, US Department of Agriculture, Ames, IA
2. Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
3. California Veterinary Diagnostic Laboratory, University of California, Davis, CA
4. Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA
5. Department of Veterinary Molecular Biology, Montana State University, Bozeman, MT (DEB); and Department of Pathology, Medical Center, University of California, San Diego, CA
6. Department of Pathology, Medical Center, University of California, San Diego, CA