1. Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, U.S.A. (e-mail: )
2. North Carolina State Museum of Natural Sciences, 1626 Mail Service Center, Raleigh, North Carolina 27699-1626, U.S.A. (e-mail: )