The committee further defined its infections of focus according to the likelihood that the primary infection would be subacute or the infected person would be asymptomatic for days to years, and the adverse health outcome would begin months to years after infection. In such cases, diagnosis of the long-term adverse health outcome during military service in Asia would be unlikely, and such infections were candidates for in-depth review and conclusions. In contrast, military medical personnel would probably diagnose adverse health outcomes that are manifest during the acute illness or shortly after a person’s deployment.
Finally, the committee examined the likelihood that the candidate infections would have occurred specifically during military deployment to southwest and south-central Asia during the three operations in question. The risk of contracting the disease in the theater of operations must have been equal to or greater than the risk of contracting it in the United States. Moreover, given the natural history of the disease or infection, it must have been diagnosed in US troops in appropriate temporal relationship to deployment.
By applying those criteria to the dozens of infectious diseases recognized initially, the committee identified the group that required in-depth evaluation and conclusions: brucellosis, Campylobacter infection, leishmaniasis, malaria, Q fever, salmonellosis, and shigellosis. Two other diseases did not meet all the criteria but still merited in-depth evaluation: tuberculosis and West Nile virus infection.
Tuberculosis (TB) could cause long-term adverse health outcomes in US troops and veterans deployed to southwest and south-central Asia, where TB is highly endemic. TB has a long history of activation and transmission in military settings. Moreover, about 2.5% of military personnel deployed to OEF and OIF and given predeployment and postdeployment skin tests for TB converted from negative to positive; that is, these troops acquired new TB infections during deployment.6 Therefore, although the committee found no published reports of active TB cases among the troops in question, conclusions about the long-term adverse health outcomes of TB infection are quite pertinent.
Unlike TB, West Nile virus (WNV) has been reported in troops deployed to southwest and south-central Asia, where the virus is endemic. The long-term adverse health outcomes associated with WNV infection are usually manifest during the acute illness—a characteristic that disqualified other diseases from comprehensive evaluation in this report. Nevertheless, dramatic changes in the epidemiology of WNV since the mid-1990s led the committee to make an exception for WNV and to review it in depth.
In addition, a small set of biologic agents, infections, and diseases that failed to meet the committee’s inclusion criteria nevertheless raised serious questions that merited discussion: Al Eskan disease, biowarfare agents, idiopathic acute eosinophilic pneumonia, mycoplasmal infection, and wound infection (including wound infection caused by Acinetobacter baumanii, the most notable pathogenic colonizer of wounds during OEF and OIF).
Conducting extensive searches of the biomedical and epidemiologic peer-reviewed literature on the diseases identified for study yielded about 20,000 potentially relevant