1. Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT;
2. Institute for Stem Cell Biology and Regenerative Medicine, and the Ludwig Center for Cancer Cell Research, Stanford University School of Medicine, Stanford, CA;
3. Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT;
4. Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany; and
5. Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard, Cambridge, MA