1. United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory Beltsville Maryland
2. Department of Biomedical Science and Pathology, Virginia–Maryland College of Veterinary Medicine Virginia Tech Blacksburg Virginia
3. Molecular Parasitology Section, Laboratory of Parasitic Diseases, National Institutes of Health, National Institutes of Allergy, and Infectious Diseases Bethesda Maryland