Background: Much concern has been expressed about the high prevalence of tuberculosis in prisons in industrialised countries. Since there is almost no information from developing countries, we investigated the rate of pulmonary tuberculosis in a large prison in Malawi.
Methods: Between May and July, 1996; we carried out an active case-finding survey in Zomba Central Prison, Malawi, through the National Tuberculosis Control Programme. We interviewed prisoners, and those with a cough of at least 1 week's duration were screened by sputum-smear microscopy. If microscopy was negative, prisoners underwent chest radiography. We offered HIV testing, with voluntary consent and counselling before and after tests, to all prisoners, whether positive or negative for pulmonary tuberculosis.
Findings: 914 (70%) of 1315 prisoners were screened (905 men, nine women; mean age 30 years [SD 11]). 47 (5%) screened prisoners (all men) had pulmonary tuberculosis: 14 were taking antituberculosis treatment and 33 were undiagnosed at the start of the study; 18 were sputum-smear positive and 15 were sputum-smear negative. 16 (73%) of 22 prisoners with previously undiagnosed pulmonary tuberculosis and 30 (75%) of 40 prisoners with cough but no evidence of pulmonary tuberculosis were HIV seropositive. In all prisoners, except one, symptoms of pulmonary tuberculosis had developed after they had entered prison.
Interpretation: We found a high rate of pulmonary tuberculosis in Zomba Central Prison, which suggests active transmission of tuberculosis. As a result of this study, the National Tuberculosis Control Programme has implemented interventions in eight prisons in Malawi to improve tuberculosis control, including collection of health data, education of prisoners and clinical staff about tuberculosis, active screening of prisoners for pulmonary tuberculosis by sputum-smear microscopy, and active case-finding in the prisons.