1. Field Veterinary Program, Wildlife Conservation Society, 185th Street and Southern Boulevard, Bronx, New York 10460, USA
2. Current address: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, Pennsylvania 19104, USA
3. HelmWest Laboratory, 2108 Hilda Avenue, Missoula, Montana 59801, USA
4. World Wildlife Fund, Dzanga-Sangha National Park, Bayanga, Central African Republic
5. Current address: Department of Animal Health, Smithsonian's National Zoological Park, Washington, DC 20008, USA