1. Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada
2. Department of Pathology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada
3. Veterinary Sciences Division, Department of Agriculture, Stoney Road, Stormont, Belfast BT4 3SD, UK
4. Harding Swine Veterinary Services Inc., Box 2922, Humboldt, SK S7N 5E3, Canada (Harding)
5. Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210–1092