1. 1William T. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA
2. 2Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA
3. 3Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California-Davis, Davis, CA