1. University of Wisconsin-Madison, Madison, Wisconsin, USA;
2. Animal Health Laboratory, Guelph, Ontario, Canada;
3. Canadian Science Centre for Human and Animal Health, Winnipeg, Manitoba, Canada;
4. Ontario Ministry of Agriculture, Food, and Rural Affairs, Guelph, Ontario, Canada;
5. Swine Services Group, Stratford, Ontario, Canada;
6. Ontario Ministry of Health and Long Term Care, Clinton, Ontario, Canada;
7. Ontario Ministry of Health and Long Term Care, Toronto, Ontario, Canada