1. Siberian Tiger Project, Wildlife Conservation Society, 2300 Southern Blvd., Bronx, New York 10460, USA
2. Department of Veterinary Clinical Sciences and Washington Animal Disease Diagnostic Laboratory, College of Veterinary Medicine, Washington State University, PO Box 647034, Pullman, Washington 99164-7034, USA
3. Department of Veterinary Microbiology and Pathology, and Washington Animal Disease Diagnostic Laboratory, College of Veterinary Medicine, Washington State University, PO Box 647034, Pullman, Washington 99164-7034, USA
4. Henry Doorly Zoo, 3701 S 10th Street, Omaha, Nebraska 68107, USA
5. University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa