1. Department of Clinical Studies Section of Dermatology School of Veterinary Medicine University of Pennsylvania 3800 Spruce Street Philadelphia PA 19104 USA
2. Department of Pathobiology School of Veterinary Medicine University of Pennsylvania 3800 Spruce Street Philadelphia PA 19104 USA
3. Department of Medicine and Epidemiology School of Veterinary Medicine University of California 1 Garrod Dr Davis CA 95616 USA