RELATIONSHIPS OF PAST TUBERCULIN REACTION, PAST BCG INOCULATION, AND CALCIFIED FOCI, TO TUBERCULOSIS IN SCHOOL PUPILS

Abstract

Eighty nine hundred fifty-six pupils of 17 primary schools in Kawasaki city, who entered school during the years 1955-1958, were followed up till their graduation. A total of 81 tuber culosis morbid cases were found in their school life. The relationship between the incidence of tuberculosis morbid case and the maximal intensity of tuberculin reaction before detection of their diseases was as follows: 5.2% in marked positive group (redness over 10mm in di ameter with induration and duplicate redness against 1: 2000 OT), 1.0% in moderate positive group (redness over 10mm with induration), and 0.1% in feeble positive group (redness over 10mm only). A total of 147 cases with calcified primary pulmonary and hilar nodes foci were found during the period of observation. The incidence of the cases with calcified foci in relation to the maximal intensity of tuberculin reaction before detection of their diseases indicated similar result: 7.3% in marked, 1.7% in moderate, and 0.2% in feeble positive group respectively. Those who showed feeble positive reaction alone before detection of thei r diseases were only 7 cases in number, 6 of these showed moderate or marked positive reaction afterdetection of their diseases. Another case showed feeble positive reaction through his school life, however he showed redness over 30mm 1 year before the detection of disease. Of the cases with calcified foci, 3 cases showed feeble positive reaction through their school life. One out of these 3 also showed redness over 30mm. After entrance in junior high school, both of these 2 cases showed induration by the unused site examination.
As to the relationship between the size of redness and the appearance of induration, 403 cases with redness over 10mm were examined. Those with redness less than 14mm showed no induration. On the contrary, of those with redness over 30mm, 91% showed induration. Four hundred thirty-nine cases, who showed induration at least once or more times through their primary school life, were tested by the unused site injection in the 1st grade of the junior high school. Of them 65% showed induration. Of 593 cases who showed redness only through their primary school life, 21% showed induration by the unused site injection in the 1st grade of the junior high school. The correlation of the size of redness in the used site and the appearance of induration in the unused site, was not present in the former. However, the correlation was present, to some degree, in the latter.
Of 81 tuberculosis morbid cases of the primary schools, 43.2% had the history of previous BCG inoculation. Thirty morbid cases and 15 morbid cases, detected in 1963 respectively from all the junior high schools and 4 high schools in Kawasaki city, had been inoculated with BCG in 26.3% and 33.3% respectively. Of the morbid cases of the junior high schools, 57% had calcified foci, and none had the history of BCG inoculation.