1. William R. Pritchard Veterinary Medical Teaching Hospital, University of California; Davis CA 95616 USA
2. Departments of Pathology, Microbiology, and Immunology; University of California; Davis CA 95616 USA
3. Population Health and Reproduction, University of California; Davis CA 95616 USA
4. Surgical and Radiological Sciences; University of California; Davis CA 95616 USA