[Tuberculous infection and prevention]

In Japan, the number of tuberculosis infected patients has been increasing again, especially in the elderly. The incidence of newly registered tuberculosis patients who are over 70 years is 34%. The outbreak of tuberculosis also has been increasing, and has become a serious social problem. The elderly have a high risk of developing tuberculosis because of their immunosuppressed condition due to underlying disease and aging. Elderly active tuberculous people also confer a risk of tuberculosis infection to the non-tuberculosis infected young generation. In this symposium, we discussed about 1) the tuberculosis outbreak related to the strategy for tuberculous prevention, 2) the health examination to detect tuberculous people in the middle-aged and elderly, 3) the nosocomial transmission of tuberculosis in the hospital, 4) the nutritional damage and immunosuppressive state in elderly people related to developing active tuberculosis in latent tuberculous infection, and 5) the organ transplantation and tuberculosis focusing on living related liver transplantation. Seven cases of tuberculosis outbreak were reported in Osaka from 1989 to 1998, 2 cases in the hospital and 5 in others. Tuberculous infection index (maximum sputum Gaffky score multiplied by the number of months of persisted cough) was 8 and 15 in the hospital, 3, 0, 84, 14, and 27 in others. Three cases (43%) were observed in persons with less than 10 of this index. It is essential to evaluate carefully for tuberculosis outbreak in extraordinary examination, if the tuberculous infectious index is low. There are various immunosuppressive patients with malignancy and other underlying disease in the hospital, so we have to pay careful attention for tuberculous outbreak when there is an active tuberculous patient. In these seven cases of extraordinary examination for tuberculous epidemic, only one (0.4%) of 241 cases who received isoniazide prophylactic therapy developed active tuberculosis. Isoniazide prophylactic therapy was an important strategy for the prevention of tuberculous outbreak. (Isamu TAKAMATSU, Osaka Prefectural Habikino Hospital, Osaka). It is essential to prevent tuberculosis in the elderly to achieve tuberculosis control in public health. The health examination was an important strategy for the detection of tuberculosis in the middle-aged and elderly. The incidence of tuberculosis detection is only 9.3% by the health examination at this age. However, the health examination has well detected active tuberculosis patients in elderly (34.5%), and also 16.8% in smear positive cases with pulmonary cavitary formation. The early detection of persons with active tuberculosis is essential, and further discussion regarding cost-performance and accuracy of the health examination for tuberculosis should also be essential. Prophylactic therapy of isoniazide also might be considered for the high risk middle-aged and elderly people with underlying diseases. (Masako OMORI et al., Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo). The cases of nosocomial transmission of tuberculosis in the hospital have been increasing. In younger persons, the incidence of tuberculosis infected nurses and doctors is relatively higher than healthy control. The transmission of tuberculosis from elder active tuberculosis patients to healthy non-tuberculosis infected medical workers has been well recognized. It is very essential to follow guidelines for the prevention of tuberculous transmission in the hospital from the Japan Tuberculosis Society including routine tuberculin skin test for fresh medical workers. Primary education for tuberculosis in medical and nursing school is also an important strategy. Further discussion might be essential that BCG could prevent tuberculosis transmission in tuberculin skin test negative adults. (ABSTRACT TRUNCATED)