1. Emerging Infectious Diseases Branch, Center for Infectious Disease Research, Walter Reed Army Institute of Research , Silver Spring, Maryland , USA
2. United States Military HIV Research Program, Center for Infectious Disease Research, Walter Reed Army Institute of Research , Silver Spring, Maryland , USA
3. Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc , Bethesda, Maryland , USA
4. Diagnostics and Countermeasures Branch, Center for Infectious Disease Research, Walter Reed Army Institute of Research , Silver Spring, Maryland , USA
5. Infectious Disease Service, Brooke Army Medical Center , Fort Sam Houston, Texas , USA