1. Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
2. London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario, Canada
3. National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
4. Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
5. Department of Biology, University of Western Ontario, London, Ontario, Canada