HTLV-I and HTLV-II are human retroviruses discovered just prior to HIV. They are important because they 1) infect up to 14 million (HTLV-I) and several million (HTLV-II) people worldwide; 2) cause hematologic, neurologic and autoimmune disease (HTLV-I) and neurologic disease together with increased susceptibility to bacterial infections (HTLV-II); and 3) serve as models for the epidemiology and pathogenesis of other human retroviral infections such as HIV. The International Conference on Human Retrovirology: HTLV and Related Viruses is a biennial conference which serves to unite the global community of HTLV researchers at the only regular international meeting devoted exclusively to HTLV infection. Three hundred to 350 scholars from HTLV-endemic regions and international infectious disease research institutions gather at this biennial meeting to present their latest data on the molecular virology, immunology, epidemiology and clinical outcomes of HTLV infection. Historically the meeting has been held in HTLV-endemic areas such as Hawaii, Jamaica, Trinidad, Brazil, and southeastern Japan, or at international research centers such as Paris and Dublin. The 2002 meeting planned for San Francisco will be the first USA meeting since 1994, and the organizers plan to emphasize research themes relevant to San Francisco and the USA, namely injection drug use-related HTLV-II and transfusion transmission viral infections. The San Francisco venue will allow more US junior scientists and students to attend due to lower domestic travel costs, fulfilling our goal of encouraging a new generation of HTLV researchers. In order to encourage the continued strong participation of attendees from developing countries with endemic HTLV infection, this grant application seeks to defray meeting expenses and keep registration fees affordable. The objectives for the XI Conference on Human Retrovirology: HTLV and related Viruses in San Francisco are: To provide a forum for the presentation of original research pertaining to HTLV-I, HTLV-II and related human and primate viruses; To promote interdisciplinary interaction between basic scientists, epidemiologists and clinical researchers toward fostering "bench to bedside" research; To promote interaction between scientists in the developed and developing world, and to stimulate international collaboration; and To expose students and young scientists to the HTLV research arena and promote their research careers.