New Admissions and Asymptomatic TB Cases fuel TB Epidemic in Prisons, a Cross Sectional Survey in Tanzania

BackgroundThere is an increased risk for tuberculosis (TB) infection and disease progression in prison settings. TB prevalence in prisons of high and middle/low income countries have been measured to be between 5 and 50 -times higher than in the general population. MethodsWe performed TB active case finding in five central prisons, Keko, Segerea, Ukonga, Butimba and Ruanda prison in Tanzania, using the Xpert MTB/RIF(R) assay on early morning or spot sputum sample from inmates and new entries between April 2014 and July 2015. ResultsOut of 13,868 prisoners tested, 13,763 had valid results. TB prevalence was 1.55% (214/13,763); new admissions contributed to the majority (61.68%) of TB cases, but prevalence was higher among inmates (1.75%) compared to new admissions (1.45%). Ukonga, an urban prison which incarcerates long-term convicted inmates had the highest prevalence of 4.02%. Male gender (OR=2.51, p<0.001), repeated incarcerations (OR=2.85, p<0.001), history of TB treatment (OR=1.78, p =0.002), TB symptoms (OR=2.78, p=0.006) and HIV infection (OR=2.86, p=0.002) were associated with positive TB results. ConclusionNew admissions could be the driving force of the TB epidemic in the penitentiary system. However, prison environments remain a major risk factor for developing active TB disease.