1. Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Prince Edward Island, Canada
2. Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Prince Edward Island, Canada
3. Department of Companion Animals, Atlantic Veterinary College, University of Prince Edward Island, Prince Edward Island, Canada
4. Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana, IL