Tuberculosis transmission in the family

Objective: To evaluate the risk of tuberculosis (TB) transmission from fami ly members with infectious TB to other family members, and to examine wheth er household contact investigations had an impact on tuberculosis patterns. Design: Under the direction of the Taipei Municipal Chronic Disease Hospita l, 12 full-time public health nurses recruited the household contacts of TB patients. Chest X-ray examination was recommended for adult contacts. Chil d contacts received the Mantoux tuberculin skin test, and radiography was r ecommended if the results were positive, Setting: Family contacts of all TB index patients who attended one of 29 hospitals in Taipei, from July 1993 through June 1996, The medical records of index patients were obtained from the National Tuberculosis Registry. Results: During the study period, the families of 3903 index patients, comp rising 11873 contacts, were investigated. Among these, 4595 received radiog raphy, for a response rate of 38.7%, Of these, 254 had active pulmonary dis ease: 188 (66.3%) had minimal disease, 79 (27.8%) had moderately advanced d isease, and only 17 (5.9%) had far advanced disease. Overall, the index pat ients had more advanced TB: only 1261 (32.3%) had minimal disease, while 20 22 (51.8%) had moderately advanced disease and 620 (15.9%) had far advanced disease. Conclusions: These data show a relatively high risk of intrafamily TB trans mission, Our findings also show that family contact investigations may help to diagnose TB in earlier stages. Such an approach should greatly reduce t he number of new TB cases and speed eradication of the disease. (C) 2000 Th e British Infection Society.