1. Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens 30602
2. Minnesota Department of Natural Resources, St. Paul 51555
3. College of Veterinary Medicine, Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul 55108
4. College of Veterinary Medicine, Minnesota Veterinary Diagnostic Laboratory, University of Minnesota, St. Paul 55108.