0% cumulative incidence, as measured by TST conversion after travel. Although estimates varied considerably from one study to another, stratified estimates were similar. In particular, cumulative incidence varied little between military and civilian travelers (2.0% vs 2.3%) despite the heterogeneous nature of activities in which

civilian travelers and deployed military units engage. Our pooled risk estimate of 2.0% is similar to the risk seen in the only prospective published study (Cobelens et al., 1.8%).3 To our knowledge, this is the first comprehensive effort to determine a pooled estimate of TST conversion, used as a surrogate for risk for LTBI, among long-term travelers. Because we were able to obtain both published and unpublished data from a variety of military and civilian sources, we believe that we have captured RO4929097 a robust

sample of Navitoclax cell line travel experiences, increasing our confidence in the applicability of our estimate to similar populations. Our comprehensive search strategy with various overlapping approaches enabled us to retrieve relevant studies and surveillance data collected systematically since 1990. Finally, two reviewers independently completed screening and study selection, increasing the reliability of the estimates. The differences between deployed military members and long-term civilian travelers may lead to concerns about generalizability of these results. However, the stratified estimates of military and civilian risk for infection were similar. Additionally, while military personnel are different in many ways from civilian populations, military exposures to local populations during deployment often approximate those of civilian travelers. For example, many long-term civilian business and vacation travelers may stay in hotels and resorts, except for transient trips out into the surrounding area for sight-seeing, activities, and shopping. Similarly, many military personnel stay on secured bases except

for transient trips out into the surrounding Dimethyl sulfoxide area for patrols and operations. These are probably low-risk situations for most members of these populations because of limited contact with infectious individuals. Conversely, both civilian aid workers and military personnel may engage in humanitarian assistance operations and work in health care settings among populations with a potentially high prevalence of disease. Close exposure of many Peace Corps Volunteers to local populations is paralleled by the exposure of members of military Provincial Reconstruction Teams and Civil Affairs and Special Operations units, who also often live in the communities and among the populations with whom they work. It appeared from our incidence density results that the data violated the assumption of a constant rate of infection over time, as evidenced by an apparent decrease in conversion rates as average travel duration increased.