1. Centre for Public Health and Zoonoses, University of Guelph, Guelph, Ontario, Canada.
2. Department of Population Medicine, Ontario Veterinary College, Guelph, Ontario, Canada.
3. Centre for Food-borne, Environmental, and Zoonotic Infectious Diseases, Public Health Agency of Canada, Guelph, Ontario, Canada.
4. Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada.