Investigation of tuberculosis contacts in a nonhospital pneumology practice

The aim of this study was to analyze the results of the tuberculosis contact tracing carried out in an outpatient pneumology setting and to assess its performance with regard to the detection of new cases of tuberculosis and infected contacts. One thousand two hundred and twenty-eight contacts of 302 tuberculosis patients were evaluated in the Tuberculosis Unit of the Dr. Fleming Specialities Center between 1992 and 1996. Contacts were categorized into groups with regard to bacteriological status of the index case (Group A, smear-positive; Group B, culture-positive only; Group C, smear- and culture-negative) and intimacy of exposure to the index case (close or casual). The possible association between the existence of infection or disease and the bacteriological status of the index case and degree of intimacy of exposure was analyzed. There were 582 infected contacts (47.4%) and 42 new cases of tuberculosis (3.4%), six of which were smear-positive. The proportion of infected and diseased contacts was significantly higher for those who had contact with smear-positive patients and those who had close contact with the index case. Chemoprophylaxis was completed in 431 (35.1%) of the contacts evaluated. Systematic investigation of contacts represents an efficient means of discovering new cases of tuberculosis and infection, especially among contacts of smear-positive index cases and among those who are closer to the index case. The administration of appropriate treatment to these contacts will contribute to controlling the transmission of tuberculosis within the community.