Transmission of tuberculosis in a jail

Background: Outbreaks of tuberculosis are uncommonly recognized in jails. In 1996, an increase in active tuberculosis cases was noted among inmates of a large urban jail. Objectives: To determine the source and extent of a tuberculosis outbreak in an urban jail and to recommend control measures. Design: Retrospective cohort study. Setting: Urban jail. Patients: Inmates and guards with tuberculosis. Intervention: Outbreak evaluation and control. Measurements: Medical records of inmates and guards with tuberculosis were reviewed, and inmates were interviewed. DNA fingerprinting was performed on Mycobacterium tuberculosis isolates. Results: From 1 January 1995 through 31 December 1997, active tuberculosis was diagnosed in 38 inmates and 5 guards from the jail. Nineteen (79%) of the 24 culture-positive inmates had isolates with DNA fingerprints matching those of other inmates. Isolates from both culture-positive guards matched the predominant inmate strain; only 6 (14%) of 43 isolates from infected persons in the community had this pattern. The median length of incarceration of all inmates in the jail was 1 day; the median length of continuous incarceration before diagnosis of tuberculosis in inmates was 138 days. Inmates with tuberculosis had been incarcerated a median of 15 times. Forty-three percent of persons in this city with tuberculosis diagnosed from January 1995 through July 1997 had been incarcerated in the jail at some time before diagnosis. Conclusions: Traditional and molecular epidemiologic investigations suggest that tuberculosis was transmitted among inmates and guards in an urban jail. Aggressive measures to screen for active tuberculosis upon incarceration are important for preventing spread of disease in jails and to the surrounding community.