A SCHOOL-BASED AND COMMUNITY-BASED OUTBREAK OF MYCOBACTERIUM-TUBERCULOSIS IN NORTHERN ITALY, 1992-3

In late 1992, three cases of smear-positive tuberculosis were diagnose d among secondary school students in Lodi, Italy. The three attended d ifferent schools but travelled on the same bus. Schoolmates, other bus riders, family members, and friends underwent tine testing and X-rays . Of the 3188 students tested, 277 (8.7%) were reactors. Independent r isk factors for tine reactivity among students included living in the same town (odds ratio [OR] = 4.8; 95% confidence intervals [CI] = 3.8- 6.0); having classroom contact (OR = 4.4; 95% CI = 3.4-5.7); or riding the same bus (OR = 5.4; 95% CI = 4.3-6.7) as a smear-positive case. T wenty-four cases of pulmonary tuberculosis were identified. The index case was a student whose father had had cavitary tuberculosis. Despite being tine test positive in 1989, he was not given prophylaxis and wa s lost to follow-up. This large outbreak. emphasizes the need for iden tification and prompt chemoprophylaxis of reactors, especially in vuln erable adolescent populations.