1. Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA
2. William R Pritchard Veterinary Medical Teaching Hospital, Davis, CA, USA
3. Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA
4. Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA