Seroepidemiology of adult T-cell leukemia virus infection and analysis of sero-positive cases in Taiwan.

For a seroepidemiologic study of adult T-cell leukemia virus (ATLV) infection in Taiwan, the gelatin particle agglutination technique and the indirect immunofluorescence method were used for anti-ATLV titration. Sporadic sero-positive cases were found all over the Taiwan districts except among the aborigines (0/947). Sero-positive rates ranged from 0 to 5.6% (except ATL family) and a total of 48 cases were found in 3682 Han-Chinese. Among them 9 cases were newly found in family surveys, and 39 cases were observed in random samples. As an average positive rate was 1.0%, by calculation about 80,000 sero-positive cases are supposed to be present in Taiwan. A most remarkable feature of the sero-positive cases was the high rate in couples. Various patterns of sero-positive cases existed in pedigrees. Anti-ATLV positive sera of Chinese living in Taiwan and Japanese were compared by immunoprecipitation and there was no difference between them. The possible infection route from Japan to Taiwan is discussed.