1. Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
2. Merck Science Center, Cambridge, MA 02141, USA.
3. Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
4. BioCryst Pharmaceuticals, Birmingham, AL 35244, USA.
5. Wisconsin National Primate Research Center, Madison, WI 53715, USA.
6. National Microbiology Laboratory, 1015 Arlington Street, Winnipeg, R3E 3R2 Manitoba, Canada.
7. Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA.