Tuberculosis in the munduruku indigenous group in the Brazilian Amazon: a public health challenge

ABSTRACT

The objective of this paper was to screen for active tuberculosis (TB), to estimate the prevalence of Mycobacterium tuberculosis (MTB), and to identify factors associated with latent tuberculosis in an indigenous population from the Brazilian Amazon. A cross-sectional study with a convenience sample of 1,213 individuals from the Munduruku indigenous group from the Tapajós River in the Jacareacanga municipality, Pará State was done. Interviews were held and tests were performed on sputum smear microscopy and culture, tuberculin skin tests (TST), and chest X-rays. The software Statistical Package for the Social Sciences was used for statistical procedures; X2 test, univariate and multivariate analyses, p value <0.05, and 95% CI were considered. The Odds Ratio was used as an association measure. Seventy cases of respiratory symptoms were identified (5.8% of study population), of whom one case was confirmed Mycobacterium tuberculosis (MTB) infection, achieving a punctual prevalence of 82.4/100,000. 219 chest x-rays were performed, 40 (18.3%) of which showed abnormalities. The prevalence of TST with reactions ≥10mm was 22.0% and 37.4% for the 5mm cut-off point. The TST reactions ≥10mm were associated with village of residence, age over 40 years, male gender, contact with a TB patient, and the presence of a BCG vaccine scar. The rate of respiratory symptoms was markedly higher when compared to the non-indigenous population. Although some adults could have been infected years previously, the high prevalence of infection and its strong association with ages under 40 years, indicate ongoing contact with TB patients