1. Departments of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA, USA
2. Centro VISAVET, Universidad Complutense de Madrid, Madrid, Spain
3. Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, USA
4. Neuropathology Division, Department of Pathology, School of Medicine, University of California, San Francisco, San Francisco, CA, USA