Tuberculosis mass survey was carried out on the inhabitants of Okierabu-island (1961) and Setouchitown (1962) successively. In the present paper, relationship between the prevalence of tuberculosis and the experience of life outside these islands was presented, and further, general discussion was made on tuberculosis in Amami-islands.
1) Positive rate of tuberculin reaction in these islands were obviously lower than the average of Japan. Among them, the rate was highest in Okierabu-island (59.0%) and lowest in Setouchi-town (45.5%), and in Tokunoshima-town it was inter mediate.
2) Tuberculin positive rate by age shows that the rate was very low in the age groups younger than 30 years old and increased very steeply to the rate of rural area of Japan at 30 years old. In the age groups 40-50 years old, the rate reached to the figures in the urban area of Japan.
3) X-ray examination revealed that the preva lence of tuberculosis was highest in Okierabu-island and lowest in Setouchi-town, but generally speaking, prevalence of tuberculosis in these islands was obviously lower than the average of Japan. On the other hand, the rate of cavitary tuberculosis in Okierabu-island and Tokunoshima-town was about the same to the average of Japan.
4) Relationship between tuberculosis and the experience of life outside island was checked in Okierabu-island on the inhabitants of older than 20 years to analyse the mode of tuberculous infection. Persons who have had the experience of life outside this island for longer than one year was 40.4 %, and the rate was higher in male than in female. Among tuberculous patients, the rate of persons with the experience of life outside island was higher than in non-tuberculous persons.
It seems likely that tuberculosis was imported to the islands in the majority of cases after getting infection in elsewhere outside the island, just like the rural area of Japan in the past. Low tuberculin positive rate among younger age groups and high rate in older age groups observed in these islands mentioned in paragraph3) might be explained by the fact mentioned above.
5) In these islands, living standards are very low both economically and hygienically. In spite of such a poor living conditions, the accumulation of active tuberculosis among household was similar to the average of Japan, whereas the rate of house holds with active tuberculosis to the total housholds was lower than that of Japan.
Accordingly, it seems that tuberculosis which was imported from elsewhere outside the islands did not spread so widely in these islands. This may due partly to the less chance of infection caused by the good climate, inconvenience of transportation, and no facilities for entertainment where many people come into contact, etc.
6) In addition to give intensive treatment for already detected patients, tuberculosis control program should be conducted in these remote islands in such a way to vaccinate people with BCG when they go out from the islands to get jobs, and to examine those who come back again after certain period of stay outside the islands.
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