Ilse U. Silva-KrottFrom the Department of Pathobiology, College of Veterinary Medicine, The University of Tennessee, PO Box 1071, Knoxville, TN 37901-1071.
Russell L. TuckerFrom the Department of Pathobiology, College of Veterinary Medicine, The University of Tennessee, PO Box 1071, Knoxville, TN 37901-1071.