1. Department of Comparative Medicine, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37901
2. Virginia—Maryland Regional College of Veterinary Medicine, Phase II, Duckpond Drive, Blacksburg, VA 24061-0442
3. Department of Large Animal Clinical Sciences and Microbiology, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824