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