Basic epidemiology of tuberculosis in Peru: a prevalence study of tuberculin sensitivity in a Pueblo joven.

Tuberculosis continues to cause significant morbidity and mortality in developing nations. As a first step in defining the magnitude of the problem in Peru, we determined the prevalence of tuberculin sensitivity in an age-stratified, community-based population on the outskirts of Lima in December 1990. The overall prevalence of 10 mm or more induration in 368 individuals was 34%. When stratified by age, the prevalence was 12% in the 0-1-year-old group, 18% in the 2-4-year-old group, 24% in the 5-14-year-old group, 60% in the 15-24-year-old group, and 68% in the > or = 25-year-old group. Vaccination with bacillus Calmette-Guerin (87% of the study population) caused significant increases in weak (5-9 mm) reactions to purified protein derivative, but did not cause strong (10 mm or more) reactions. The prevalence of tuberculous infection in this population is higher than that previously reported in Peru and in most other high-risk populations. Unfortunately, the current political and economic situation in Peru makes it difficult to implement public health measures to prevent infection and progression of infection to disease.