HTLV-I carriers among migrants from an ATL-endemic area to ATL non-endemic metropolitan areas in Japan.

The prevalence of antibodies against HTLV-I among Kyushu natives aged 16 to 39 years who moved from Nagasaki and Kagoshima prefectures to Aichi prefecture (a non-endemic area for ATL) was compared by their cities or counties of birth. The positive rate of anti-HTLV-I antibody was 2.4% (II/400) among Nagasaki natives, 6.4% (20/312) among Kagoshima natives and 4.0% (31/772) for both combined. There was a slight difference in the positive rate of anti-HTLV-I antibody between Kyushu natives from cities (3.3%) and from counties (4.5%). In county areas, the prevalence of anti-HTLV-I antibodies among migrants from areas of relatively higher mortality for malignant lymphomas (7.5%) was significantly higher (p less than 0.01) than among persons from lower mortality areas (1.9%). Most "positive" persons had moved from Kyushu to Aichi prefecture between the ages of 15 and 18 years. The results of the present study suggest that: there is a considerable number of HTLV-I carriers among Kyushu natives who have settled in ATL non-endemic areas, especially among those born in regions of Kyushu district which have a high mortality rate for malignant lymphomas; and that Kyushu natives who had settled in metropolitan areas might have been exposed to HTLV-I during childhood in their birthplace.