An epidemic of tuberculosis with a high rate of tuberculin anergy among a population previously unexposed to tuberculosis, the Yanomami Indians of the Brazilian Amazon

摘要

A survey of an emerging tuberculosis epi- demic among the Yanomami Indians of the Amazonian rain forest provided a unique opportunity to study the impact of tuberculosis on a population isolated from contact with the tubercle bacillus for millennia until the mid-1960s. Within the Yanomami population, an extraordinary high prevalence of active tuberculosis (6.4/100 of 625 individuals clinically exam- ined) was observed, indicating a high susceptibility to disease, even among bacille Calmette-Guerin-vaccinated individuals. Observational studies on cell-mediated and humoral immune responses of the Yanomami Indians compared with contem- porary residents of the region suggest profound differences in immunological responsiveness to Mycobacterium tuberculosis infection.