1. Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada
2. Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario N1G 3W4, Canada
3. Department of Microbiology and Immunology, Queen's University, Kingston, Ontario K7L 3N6, Canada
4. Faculté de Médecine Vétérinaire, Departement de Pathologie et Immunologie, Uníversité de Montréal, Saint-Hyacinthe, Quebec J2S 7C6, Canada