1. Department of Medical Microbiology and Immunology, School of Medicine, University of California–Davis, Davis, California.
2. AIDS Research Program, Ponce School of Medicine, Ponce, Puerto Rico.
3. Department of Medical Pathology and Laboratory Medicine and Center of Comparative Medicine, School of Medicine, University of California–Davis, Davis, California.
4. Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
5. Division of Virology, Children's Hospital of Eastern Ontario and University of Ottawa, Ottawa, Ontario, Canada.
6. Sonora Cancer Research Center, Sonora, Mexico.