Tuberculosis among immigrants from developing countries in the province ofMilan, 1993-1996

SETTING: The Province of Milan, which has high rates of immigration from de veloping countries, and the Villa Marelli Institute (VMI), Reference Centre for Tuberculosis Control of Lombardy. OBJECTIVE: To describe epidemiology and clinical patterns of tuberculosis a mong immigrants from developing countries (IDCs) in the Province from 1993 to 1996. DESIGN: Retrospective analysis of the registries of the Regional Bureau for Public Health and of the VMI concerning immigrant patients with active TB living in the Province. Restriction fragment length polymorphism (RFLP) ana lysis of the available strains to detect recent transmission among immigran ts. RESULTS: IDCs represented 22.8% of all TB cases. The standardised incidence rate was eight times higher in IDCs compared to Italians. Of 596 cases not ified in IDCs, 524 (87.9%) had been referred at least once to the VMI. Of t hese, 77.2% were diagnosed within 5 years of arrival, and 86.6% were brough t to medical attention because of symptoms. RFLP fingerprinting demonstrate d that the mean period of stay in Italy was significantly higher in cluster ed than in non clustered patients (61.5 versus 37.3 months). Spread to the native population was episodic. CONCLUSIONS: The incidence of TB is higher among more recent immigrants (i. e., Peruvians). TB cases are largely due to reactivation of infection occur ring in the country of origin. Preventive measures for early diagnosis of d isease or chemoprophylaxis of dormant infection are not regularly performed , but should be implemented for those immigrants at high risk.