1. Department of Population Medicine, Ontario Veterinary College, University of Guelph, 50 Stone Rd E, Guelph, ON, Canada N1G2W1
2. Veterinary Pathology Consultant, Guelph, ON, Canada
3. Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames 50011
4. Veterinary Epidemiology Consultant, Elora, ON, Canada