The burden of tuberculosis in indigenous peoples in Amazonia, Brazil.

Tuberculosis (TB) stands out as one of the principal infectious diseases affecting Amazonian Indians. Recent research indicates that incidence rates among indigenous peoples may be as much as ten times higher than those of the general Brazilian population. Purified protein derivative reactivity in Amazonia is low compared with populations of European descent; anergy rates usually surpass 50%, even under high BCG coverage. An annual risk of infection of 1.2-2.2% points to high rates of transmission. Whether or not particular susceptibility to TB is linked to genetics, Amazonian Indians face a disproportionately high risk of contracting and dying from TB.