1. Clinical Investigation Facility, David Grant USAF Medical Center, 101 Bodin Circle, Travis Air Force Base, California 94535
2. Veterinary Medical Research Institute, Hungarian Academy of Sciences, H-1581 Budapest, Hungary
3. Viral and Rickettsial Disease Laboratory, California Department of Health Services, 850 Marina Bay Parkway, Richmond, California 94804
4. Blood Systems Research Institute, 270 Masonic Ave., San Francisco, California 94118
5. University of California, San Francisco, Department of Medicine, San Francisco, California 94118