Some recent aspects of tuberculosis infection in Japan. (1).
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- AOKI Masakazu
- From the Research Institute of Tuberculosis, JATA
Bibliographic Information
- Other Title
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- 結核感染をめぐる諸問題 Ｉ
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Abstract
As BCG vaccination is compulsory for all the tuberculin negative reactors at three points during their life, namely, bef or 4 years, at 6 years and/or 12 years of age, and the coverage is as high as nearly 95%of the age six, it is found that tuberculin test is very often not reliable as a means to reveal tuberculosis infection and its result is often wrongly interpreted in Japan.As a result, the present status of tuberculosis infection is so obscure that the author was lead to make a review of recent problems regarding tuberculosis infection in Japan at this Annual Meeting.<BR>The confusions in interpreting the results of the tuberculin test originate from the following: 1) high coverage of BCG vaccination, 2) rather rapid wanning of post vaccination allergy, 3) so-called booster effect of interim tuberculin testing, 4) late appearance of tuberculin reaction among children whose post-vaccination had already waned, 5) possibility of atypical mycobacterial infection in Japan, and 6) rare occurrence of tuberculosis infection among children.All these problems were discussed briefly.<BR>All the newly registered cases of infants and children tuberculosis in Tokyo (excluding 23 wards) in this five year period were analysed.It was confirmed that as high as 28.5% of the cases were mis-diagnosed because of the difficulties of diagnosing tuberculosis in children, and the source of infection was detected in 100%of the cases under 4 years of age and in 60%of the cases of those 0-14 years of age.The severity of the disease wa almost the same between cases whose source of infection was detected and those it was not detected.<BR>Recently group infection of tuberculosis is quite often reported from primary, middle and high schools and so on, in spite of high coverage of BCG vaccination.The risk factors of the occurrence of group infection were investigated.The results show that the risk of group infection is high in patients whose sputa contain more than one tubercle bacilli in each microscopic field on smear examination, and who complained of severe coughing more than 3 months before the detection of the disease.The author discussed the possibility of the tuberculosis infection among the aged because about 20-30%of the aged showed negative tuberculin reaction in repeated tuberculin testing.<BR>The annual reduction rate of tuberculosis incidence was 11%up to 1977, but it decreased to a rate of 5.5% there after.This slowing down in the rate of decrease of the incidence is observed in all over Japan, and is marked among younger generations less than 39 years of age.Although the reason of this slow-down is not clear yet, one can say that this is not caused by the artificial factors such as the change of diagnostic criteria, reporting rate, BCG vaccination policy and so on. The possible reasons for the decrease in the rate of decrease in the risk of tuberculosis infection was discussed.
Journal
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- Kekkaku(Tuberculosis)
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Kekkaku(Tuberculosis) 63 (1), 33-38, 1988
JAPANESE SOCIETY FOR TUBERCULOSIS
