Infection risk of sputum positive tuberculosis patients to their family contacts with and without chemotherapy.

Infectivity of Sputum smear positive patients with tuberculosis for household contacts was assessed before diagnosis and during domiciliary treatment. Intracutaneous tuberculin test, sputum and radiological examinations were done in all cases and their house-hold contacts initially; and were repeated for contacts every six months during two years follow-up. Initially 244 (56%) contacts gave positive tuberculin reaction and 36 (8.3%) revealed lung lesions. Tuberculin conversion was detected in 14% cases during 6-month follow-up. Thereafter infection incidence reduced considerably over the following 18 months. risk before diagnosis and treatment of the index case, cooperative patients. (JPMA 35 249, 1985).