1. Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30341
2. State Agricultural Biotechnology Centre, Division of Veterinary and Biomedical Sciences, Murdoch University, Perth, Western Australia 6150, Australia
3. Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205
4. Saint Louis Zoo, St. Louis, Missouri 63110
5. Department of Parasitology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic