Tuberculosis among Yanomami communities from Alto Rio Negro,State of Amazonas, Brazil, 1990 to 2002

Background: Brazilian indigenous populations show high tuberculosis rates, which can be attributable not only to socio-economic conditions and poor access to health care services, but also to an intrinsic susceptibility of these individuals. We describe the distribution of tuberculosis cases in two Yanomami communities, and focus on the occurrence of familial clustering of TB cases. Methods: We have performed a descriptive study of TB cases in the Yanomami communities of Ariabu and Maturaca (Sao Gabriel da Cachoeira, AM, Brazil) between 1990 and 2002, based on medical records provided by health care professionals working in the area. The communities studied are located close to each other, separated by a river, but sharing the same environmental resources, with no differences in social, economic or housing conditions. Results: In this period, 101 cases of TB were registered, corresponding to an estimated annual incidence after active surveillance of 1,082/100,000 at Ariabu and 2,452/100,000 at Maturaca. Multicase families were significantly more frequent in Maturaca community, independent of family size, suggesting familial aggregation (p<0.001). Conclusions: Tuberculosis is a serious problem among the Yanomami. TB control in Yanomami communities will require improvement in housing conditions, active surveillance, contact tracing and diagnosis. Yanomami multicase families should be investigated as a potential group with hyper-susceptibility to tuberculosis.