Incidence of positive tuberculin tests by age and place of birth: a study.

In central Toronto tuberculin positive rates of 35% and 48% were found in young adult immigrants from the Caribbean and Asia. Foreign born residents, representing 22.2% of the population, contributed 68.3% of all the active cases of tuberculosis in Ontario in 1980.The incidence of active tuberculosis in Ontario in 1980 in males aged 70 years and over was 43.4 per 100,000 compared to 11.1 per 100,000 for males and females of all ages.The need for surveillance of immigrants and refugees as well as the elderly is emphasized.