The risk of tuberculosis infection and disease in this population was high. Despite the reduced incidence resulting from recent efforts, tuberculosis control requires closer surveillance of contacts and improvement in communication strategies between health teams and indigenous populations.

The presence of latent tuberculosis infection (LTBI) and active TB between children and adolescents are indicators of active and progressive transmission of Mycobacterium tuberculosis. The X-rays showed high frequencies of infiltrates and calcifications, which are compatible with primary infection in early childhood. However, these lesions are not different from those observed among other groups and do not suggest immune deficiencies. The divergences presented show that the best moment for the treatment of LTBI went unnoticed by local personnel. In conclusion, the use of a score system is fundamental for the correct diagnosis of TB in childhood, as is conducting bacilloscopy and sputum culture in adolescents able to expectorate.

Introduction:Recent studies have shown a high incidence and prevalence of latent tuberculosis infection (LTBI) in indigenous populations around the World. We aimed to estimate the prevalence and annual risk of infection (ARI) as well as to identify factors associated with LTBI in an indigenous population from the Brazilian Amazon. Methods: We conducted a cross-sectional study in 2011. We performed tuberculin skin tests (TSTs), smears and cultures of sputum samples, and chest radiographs for individuals who reported cough for two or more weeks. Associations between LTBI (TST ≥5mm) and socio-demographic, clinical, and epidemiological characteristics were investigated using Poisson regression with robust variance. Prevalence ratio (PR) was used as the measure of association. Results: We examined 263 individuals. The prevalence of LTBI was 40.3%, and the ARI was 2.4%. Age ≥15 years [PR=5.5; 95% confi dence interval (CI): 3.5-8.6], contact with tuberculosis (TB) patients (PR=3.8; 95% CI: 1.2-11.9), previous TB history (PR=1.4; 95% CI: 1.2-1.7), and presence of Bacillus Calmette-Guérin (BCG) scar (PR=1.9, 95% CI: 1.2-2.9) were associated with LTBI.Conclusions: Although some adults may have been infected years prior, the high prevalence of infection and its strong association with age ≥15 years, history of TB, and recent contact with TB patients suggest that the TB transmission risk is high in the study area.

The approach used in this study proved useful in demonstrating inequalities in health between indigenous and non-indigenous populations and was superior to the conventional analyses performed by the surveillance services, drawing attention to the need to improve childhood TB diagnosis among the indigenous population.