1. Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, NC 27606, USA, and, Department of Dermatology, University of North Carolina School of Medicine, Chapel Hill, NC 26515, USA
2. Dermatology for Animals, Campbell, CA 95008, USA
3. Department of Pathology, Microbiology and Immunology, University of California School of Veterinary Medicine, Davis, CA 27606, USA
4. Department of Biomedical Sciences, University of Bradford, Bradford BD7 1DP, UK