The incidence of tuberculosis among North Carolina migrant farmworkers, 1991

All locatable subjects (n = 94) for whom tuberculosis prevalence had been determined in an earlier study were tested with purified protein derivative (PPD) and control antigens, sputum sampling, and chest x-rays. Of the 46 who had been tuberculin negative (confirmed with control antigens) 3 years earlier, 2 had developed active tuberculosis in the interim and 14 (30%) were tuberculin positive. All had been engaged continuously in migrant farmwork. Lack of access to health care, an institutional feature of migrant farmwork, was significantly associated with primary infection.