1. The Wistar Institute of Anatomy and Biology, 36th Street at Spruce, Philadelphia, Pennsylvania 19104, USA
2. University of Pennsylvania, School of Veterinary Medicine, New Bolton Center, Kennett Square, Pennsylvania 19438, USA
3. U.S. Department of Agriculture, Agricultural Research Service, Animal Parasite Research Laboratory, Auburn, Alabama 36831, USA
4. South Carolina Wildlife and Marine Resources Department, Columbia, South Carolina 29202, USA
5. University of Georgia, Southeastern Cooperative Wildlife Disease Study, Athens, Georgia 30602, USA