[A survey of HTLV-1 carrier clinics in Japan]

Human T-lymphotropic virus type-I (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma and HTLV-1 associated myelopathy/tropical spastic paraparesis. Currently, mother-to-child transmission via breastfeeding and sexual intercourse are considered to be the two major routes for HTLV-1 infection. We surveyed four clinics in Japan (two HTLV-1 carrier clinics in non-endemic areas and one in an endemic area, and one hematology clinic in a highly endemic area) and reviewed the management of carriers. In HTLV-1 carrier clinics, more than half of visitors had learned of their infections based on an examination conducted either for blood donation or pregnancy. Although half of visitors had known of their infection more than 2 years prior to their visit, they became to visit the clinics probably due to recent awareness of HTLV-1 in public and of carrier clinics. They requested a detailed explanation, and check-ups for infection and its related diseases. In contrast, most visitors in highly endemic areas had apparently received good explanations from their primary care physicians. It is noteworthy that neither parent of more than half of the carriers who visited the two clinics in the non-endemic area had been born outside of Kyushu, a highly endemic area, indicating that carriers will disperse from known endemic areas. Configuring an appropriate and efficient system to support carriers is necessary, especially in non-endemic areas.