Challenges with diagnosing and investigating suspected active tuberculosis disease in military trainees

Between 1 January 2010 and 31 December 2016, a total of 14 U.S. and international military personnel in training at Joint Base San Antonio-Lackland, TX, were hospitalized due to suspected pulmonary tuberculosis (TB); of these, five personnel were diagnosed with active TB disease. Only one TB case had pulmonary symptoms, but these symptoms were not suggestive of TB. The incidence rate in the training population was 1.89 per 100,000 population (95% CI: 0.81, 4.42), with a higher rate when restricted to international military students attending the Defense Language Institute English Language Center. No instances of TB transmission were identified. The variety of atypical presentations and their resulting diagnostic and public health challenges prompted this retrospective review of all hospitalized cases. This case series highlights both the importance of a high index of clinical suspicion when TB is being considered in close congregate settings as well as the risk of overreliance on acid-fast bacilli staining and nucleic acid amplification testing for ruling out active pulmonary disease in young, otherwise healthy trainees. Practical solutions are suggested.