To maximize the PPV of a screening test for LTBI, a targeted testing strategy for long-term military Olaparib research buy and civilian travelers is recommended, based on exposures known to increase the risk of TB. Studies to better define higher risk groups, activities, and locations are needed. Tuberculosis (TB) infection and transmission remain one of the greatest public health threats worldwide. Although the prevalence of TB has greatly decreased

in the temperate and developed nations of Western Europe, North America, Australia, and Japan, it remains a major disease burden in tropical and developing countries.1,2 Consequently, travelers and expatriates from low-prevalence nations who travel or live in high-prevalence nations may become infected with TB.3 In the travel medicine community, however, there is debate about the risk for latent tuberculosis infection (LTBI) that results from long-term travel.4,5 Cobelens and colleagues suggested that

the risk to travelers of acquiring LTBI is similar to that of the general population in the destination country.3 A study among Peace Corps Volunteers from 1996 to 2005 reported an annual infection risk of 0.8% to 1.2% and an active TB incidence density of 68.9 per 100,000 volunteer-years,6 somewhat higher than that for the population of Brazil in 2006 (50/100,000/year).7 In contrast, Rieder suggested that many apparent TSA HDAC datasheet latent TB infections in travelers from low-incidence countries to high-incidence countries may be due to false positive tuberculin skin tests (TSTs) in this otherwise low-prevalence population.5 Pseudoepidemics of TST conversions in military populations have been reported in relation to travel,8 as well as in non-traveling Methane monooxygenase civilian populations.9–11 Although the TST is the most well-studied test we have to date

to detect the presence of LTBI, it is not a “gold standard” because it is currently impossible to know if a person is latently infected with a few viable Mycobacterium tuberculosis organisms. Due to the inherent relationship between positive predictive value (PPV) and prevalence of infection, many TST conversions may actually be false positives in a low-risk travel population. Thus, the PPV of a TST conversion in low-risk travelers is probably less than 50%, and may be as little as 16% in the absence of a known exposure to TB.12 As a result of these conflicting estimates of risk and the inherent limitations of the TST, there is uncertainty as to the value of TST screening among long-term travelers, which leads to variability in screening policies and recommendations.