1. Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California–Davis, Davis, CA, USA
2. Department of Comparative, Diagnostic and Preventive Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
3. Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA, USA
4. Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California–Davis, Davis, CA, USA