1. Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775, USA
2. USDA/APHIS/ADC, Denver Wildlife Research Center, Building 16, Denver Federal Center, Denver, Colorado 80225, USA
3. State of Alaska NRL (Virology-Rabies Unit), Division of Public Health, Fairbanks, Alaska 99706, USA
4. Viral and Rickettsial Zoonoses Branch, Division of Viral Diseases, Center for Infectious Diseases, Centers for Disease Control, P.O. Box 363, Lawrenceville, Georgia 30246, USA