The study was undertaken to determine transmission of Mycobacterium tuberculosis
within the prison envi-ronment. In total, 168 Aba Federal prison inmates in Nigeria were evaluated for tuberculosis (TB) by sputum-smear microscopy and sputum culture, simultaneously, and for HIV status by serology. They were sub-sequently followed up for one year for fresh Mycobacterium
-associated infection by tuberculin skin testing or for development of TB and for HIV infection or AIDS. Ninety-one (54.2%) of the 168 prison inmates had infection due to Mycobacterium,
and three (3.3%) of them were sputum-smear- and culture-positive while 41 (24.4%), including one (2.4%) with concomitant TB, were HIV-infected. In a one-year follow-up study, 11 (19.3%) of 57 tuberculin skin test (TST)- and HIV-negative inmates became TST-positive and one (1.8%) HIV-positive, eight (13.8%) of the 58 TST-positive but HIV-negative inmates developed TB, and one (1.7%) became HIV-infected: six (24.0%) of 25 TST- and HIV-positive inmates developed TB while five (33.3%) of 15 TST-negative but HIV-positive inmates became TST-positive, and one (6.7%) progressed to AIDS. The duration of imprisonment did not influence the rates of infection, and the transmission of Mycobacterium tuberculosis
did not necessarily require sharing a cell with a TB case.