Margarita Woc-Colburn,^* Suzan Murray,^* Nancy Boedeker,^* Tabitha Viner,^* Michelle L. Fleetwood,^* Tony C. Barthel,^* Kurt D. Newman,^* Carlos R. Sanchez<sup>*


*</sup>From the Smithsonian Institution's National Zoological Park, 3001 Connecticut Avenue NW, Washington, D.C. 20008-2598, USA (Woc-Colburn, Murray, Boedeker, Viner, Barthel, Sanchez); the Department of Veterinary Pathology, Armed Forces Institute of Pathology, 6825 16th Street NW, Washington, D.C. 20306, USA (Fleetwood); and the Children's National Medical Center, 111 Michigan Avenue NW, Washington, D.C. 20010-2970, USA (Newman). Present address (Sanchez): Chicago Zoological Society, Brookfield Zoo, 3300 Golf Road, Brookfield, Illinois 60513, USA. Correspondence should be directed to Dr. Woc-Colburn (margarita_woc@yahoo.com). The author(s) prepared this manuscript as part of their official duties with the U.S. Government and are unable to assign rights to the American Association of Zoo Veterinarians.