RESUMO
Over the last 20 years, the decrease in the incidence of Tuberculosis (TB) in Japan has slowed down. As of 1999, the incidence rate was 34.6 per 100,000 population in Japan, which was higher than that of the other developed countries, and the incidence rate in the city of Wakayama, one of the prefectural capital cities in Japan, during the same period was 42.9 per 100,000 population. We investigated the causes of this high incidence rate of TB in Wakayama City according to the analysis by age groups and sputum test results when patients are newly registered. Comparing our data during the period from 1.1.1998 to 12.31.1999 with data during the same period in the whole country and the rest of Wakayama Pref., the following results were obtained. Observing by age-groups, the incidence of TB in Wakayama City as well as in the rest of Wakayama Pref. and in the whole country was highest in the age-group above 70 years of age, though the rate of Wakayama City was significantly higher (146.2 per 100,000 population) than that in the rest of Wakayama Pref. (98.5 per 100,000 population) and that in the whole country (90.3 per 100,000 population). Furthermore, the incidence rate of cases diagnosed as TB without bacteriological proof in Wakayama City (57.1 per 100,000 population) was significantly higher than that of the whole country (33.7 per 100,000 population). Therefore, we concluded that one of the causes of high incidence of TB in Wakayama City was due to inappropriate method of diagnosing TB. More extensive use of sputum examination and strict evaluation of cases without bacteriological proof are desirable to increase the accuracy of TB diagnosis in Wakayama City.
