I.結核集団感染の現状と今後の対策 [in Japanese] I. OUTBREAK OF TUBERCULOSIS : THE CURRENT SITUATIONS AND PERSPECTIVE IN JAPAN [in Japanese]
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The prevalence rate of tuberculosis (TB) infection has remarkably decreased not only in young people but also in middle-aged and elderly people in Japan. On the other hand, the outbreak of TB has been increasing and has become a serious social problem. Since 1997, more than 40 outbreaks have been reported annually. TB outbreaks have occurred among persons in schools, hospitals, nursing homes, prisons, amusement facilities, day laborers'accommodations with sauna, and various workplaces.<BR>To clarify current problems concerning th e outbreak and to propose effective measures against TB outbreaks, we discussed about 1) preventable factors contributed to recent outbreaks, 2) urgent problems such as the outbreak of multidrug resistant tuberculosis (MDR-TB), 3) the collaboration of relevant organizations for outbreak inv estigation, and 4) the practical application of new technologies such as DNA fingerprinting methods (e. g., restriction fragment length polymorphism analysis). Intractable problems, by which many participants of this symposium were troubled, were as follows: 1) the problem how to diagnose the latent TB infection by the tuberculin skin test on persons who have received BCG vaccine, and 2) the problem how to provide the preventive treatment for contacts of patients with MDR-TB. To solve these problems, the development of new methods to improve the diagnosis and the treatment is essential. In addition, new approaches combining methods from conventional epidemiology, molecular biology and computerized network analysis should be used in investigation and control of TB outbreaks.<BR>1. Tuberculosis outbreak in a junior high school: Mie KUSUNOSE, Makoto TOYOTA (Kochi City Public Health Center)<BR>We experienced a large outbreak of TB in a junior high school. The index (source) patient with smear-positive pulmonary TB was a third-grade student of the school. Contact investigation was carried out in more than 700 persons. Tuberculin skin test revealed an excess of strongly positive reactors in the third?grade students. During 2 years after the detection of the source case, a total of 31 TB patients were newly diagnosed. Delayed diagnosis of the source case and poor ventilation of the classrooms were attributable to the outbreak. In addition the source patient seems to be highly infectious, because transmission following only sporadic contact was documented. Among the strongly positive reactors to tuberculin skin test of third-grade students and school staffs, out of 105persons who received preventive therapy, 2 cases (1.9% ) were newly diagnosed as TB, while out of 24 cases without preventive therapy, 6 cases (25% ) developed clinical TB.<BR>A 15-year-old man, who was compliant with preventive therapy, was found to have pulmonary TB. Drug susceptibility tests revealed that the organism isolated from this patient was resistant to isoniazid, although the organism obtained from the source patient was sensitive to isoniazid.<BR>2. Tuberculosis outbreak in the workplace: Yoshiko SUEYASU, Sachiko TANOUE, Hisashi WATANABE, Toru RIKIMARU, and Kotaro OIZUMI (The 1st Department of I n ternal Medicine, Kurume University School of Medicine)<BR>The outbreak of TB has increased in variou s workplaces. To clarify factors contributing to TB outbreaks in the office/workplace, Japanese articles published between January 1987 and November 2000 were reviewed.
Kekkaku(Tuberculosis) 76(12), 759-764, 2001-12-15
JAPANESE SOCIETY FOR TUBERCULOSIS