[1] USAF, Inst Environm & Occupat Hlth Risk Anal, Epidemiol Surveillance Div, Mol Epidemiol Branch, San Antonio, TX USA
[2] USAF, Inst Environm & Occupat Hlth Risk Anal, Epidemiol Surveillance Div, Clin Microbiol Branch, San Antonio, TX USA
[3] USAF, Inst Environm & Occupat Hlth Risk Anal, Epidemiol Surveillance Div, San Antonio, TX USA
[4] Wilford Hall USAF Med Ctr, Lackland AFB, TX 78236 USA
[5] Off AF Surg Gen, Med NBC Sci & Technol Directorate, Washington, DC USA