1. United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, MSC 218, 700 University Blvd., Kingsville, Texas 78363, USA
2. United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, San Diego, Texas 78384, USA
3. United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, National Veterinary Services Laboratories, 1920 Dayton Ave., Ames, Iowa 50010, USA
4. United States Department of Agriculture, Agricultural Research Service, Cattle Fever Tick Research Laboratory, 22675 N. Moorefield Rd., MAB 6419, Edinburg, Texas 78541, USA
5. United States Department of Agriculture, Wildlife Services, 1714 Commerce Court, Suite C, Columbia, Missouri 65202-1594, USA
6. United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, 4101 La Porte Ave., Fort Collins, Colorado 80521, USA;