1. Public Health Agency of Canada, Guelph, Ontario, Canada N1G5B2
2. Department of Population Health Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
3. Department of Food Science and Technology, University of California, Davis, CA 95616
4. Animal Diagnostic Laboratory (PADLS-PSU), Pennsylvania State University, University Park, PA 16802
5. Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD 20740