1. Foreign Animal Disease Research Unit, Agricultural Research Service, Plum Island Animal Disease Center, USDA, Greenport, NY
2. Foreign Animal Disease Diagnostic Laboratory, APHIS, Plum Island Animal Disease Center, USDA, Greenport, NY
3. National Veterinary Services Laboratories, APHIS, USDA, Ames, IA
4. Department of Veterinary Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA