1. California Animal Health and Food Safety Laboratory System, Davis branch, School of Veterinary Medicine, University of California–Davis, Davis, CA, USA
2. Departments of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California–Davis, Davis, CA, USA
3. William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California–Davis, Davis, CA, USA
4. Medicine and Epidemiology, School of Veterinary Medicine, University of California–Davis, Davis, CA, USA
5. Surgical and Radiological Sciences, School of Veterinary Medicine, University of California–Davis, Davis, CA, USA