[Influence of bronchoscopic examinations on the statistics of tuberculosis incidence]

The frequency of the modes of bacteriological examinations other than direct sputum smear were observed for a total of 955 "smear-positive" pulmonary tuberculosis cases which were notified at 7 health centres in the Metropolitan and suburban areas during 1986-1990. Of them 21 cases (2.2%) were examined for the specimens obtained by bronchofiberscopic procedures, and in 4 cases (0.4%) gastric juice was taken. The proportion of the non-sputum positivity as seen above was higher in females than in males, but it was uniform across all age group. Non-cavitary cases showed higher proportion of the non-sputum positivity than cavitary cases. There was wide variation in the frequency of these aggressive modes of examination among health centres, probably indicating the difference in the extent to which hospitals are interested in these modes of examination in each health center area. In addition to the above observed cases, there were 60 cases with direct smear positive finding of mycobacteria other than tuberculosis (MOTT). They account for 5.9% of all of 1,015 new notifications of AFB-smear positive cases. It is possible that these non-sputum "smear positive" cases, as well as the MOTT-smear positive cases may be underestimated in our study, because of the notification form not necessarily requesting to enter the type of bacteriological examinations. They may contribute to the recent upward trend of incidence rate of smear positive tuberculosis in Japan to a considerable extent.(ABSTRACT TRUNCATED AT 250 WORDS)