Tuberculosis prevalence survey in Japan

Chest X-ray examination had been used rather soon after the discovery of X-ray by Rontgen K in 1895 as it was possible to detect chest abnormality by simple radiography. After the discovery of radiophotography independently by Abreu M and Koga Y in 1936, it was applied as a method of mass screening for TB in Japan, and Imamura A made a special lecture on "The mass screening for TB" using radiophotography in 1940 in the Annual Meeting of the Japanese Society for TB. From experiences of mass screening, it was found that there were many cases of TB who do not aware of their own disease, and to know the prevalence of TB, the screening of survey subjects by X-ray examination is indispensable. Noticing the importance of mass health examination by chest X-ray, Dr. Tanaka S, then director of information division, JATAHQ, edited a book entitled "How to carry out mass health examination for TB" in 1951, then he moved to the Ministry of Health and Welfare and engaged in the preparation of the first TB prevalence survey. Random sampling technique was already developed, and health center network covering the whole country was already completed in early 1950s. Using these background, the first TB prevalence survey was conducted in 1953. TB Prevalence Survey Committee was organized asking cooperation of experts in TB, epidemiology and statistics, and the survey in sampled area was carried out by a survey team headed by the director of health center in charge of the sampled area. The survey teams engaged in the survey with enthusiasm, and the rate of response to the survey was 99.3%. The result of this survey was published in the WHO Bulletin, 1955. After the survey in 1953, the following prevalence surveys were carried out in 1958, 1963, 1968 and 1973. Outline of these surveys was shown in Table 1, and the rate of examination was high in all, except the survey in 1973. In this year, TB prevalence survey was carried out in conjunction with the national nutritional survey and the national mental health survey, and unfortunately, there were some opponent groups against the national mental health survey, which affected the rate of response to the TB survey, too. In addition to the 5 prevalence surveys, one thirds of the survey population in 1953, 1958 and 1963 was surveyed in the next year to know the incidence of TB. Follow-up survey on active TB cases found in the 1953 and 1958 survey was carried out in 1964, and similar follow-up survey was carried out in 1968 for active