1. Department of Veterinary and Biological Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota.
2. Department of Animal Science, College of Agriculture, Iowa State University, Ames, Iowa.
3. Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa.
4. Department of Veterinary Science, South Dakota State University, Brookings, South Dakota.
5. PIC, Franklin, Kentucky.
6. Department of Microbiology, Medical School, University of Minnesota, Minneapolis, Minnesota.