title: Distribution of Two Subgroups of Human T-Lymphotropic Virus Type 1 (HTLV-1) in Endemic Japan.
abstract: Endemic areas of human T-lymphotropic virus type 1 (HTLV-1) have been reported in Japan as well as tropical Africa, Central and South America and Melanesia. The existence of two subgroups, i.e., the transcontinental and Japanese subgroups, was reported in Japan. In the present study, we provide data on the ratio of the two subgroups in each endemic area and infection foci and examine the distribution of HTLV-1 in Japan and neighboring areas. A 657 bp fragment of env region of HTLV-1 proviral genome was successfully amplified for 183 HTLV-1 positive DNA samples. The subgroup determination was done by RFLP reactions using endonucleases HpaI and HinfI. The northern part of mainland Kyushu, represented by Hirado and Kumamoto, was monopolized by the Japanese subgroup, while the transcontinental subgroup ranged from 20 to 35% in the Pacific coast areas of Shikoku (Kochi), the Ryukyu Archipelago (Kakeroma and Okinawa) and Taiwan. An interesting finding in the present study is the presence of the transcontinental subgroup in Kochi, suggesting the endemicity of the transcontinental subgroup along the Kuroshio Current.
authors.affiliation: Department of Gastroenterology and Hepatology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Otani
authors.forename: Noritaka
authors.initials: N
authors.lastname: Honda
authors.forename: Pin-Cang
authors.initials: PC
authors.lastname: Xia
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Eguchi
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Toshiki
authors.initials: T
authors.lastname: Watanabe
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakao
authors.forename: Taro
authors.initials: T
authors.lastname: Yamamoto
keywords: Japanese subgroup; Kuroshio Current; human migration; transcontinental subgroup