1. Department of Medicine & Epidemiology; School of Veterinary Medicine; University of California, Davis; Davis; CA
2. Department of Pathobiology; School of Veterinary Medicine; University of Pennsylvania; Philadelphia; PA
3. The Department of Pathology; Microbiology, and Immunology; School of Veterinary Medicine; University of California, Davis; Davis; CA
4. The Department of Pathobiology; Ontario Veterinary College; University of Guelph; Guelph; ON; Canada