HUMAN T-CELL LYMPHOTROPIC VIRUS TYPE-I IN IRANIAN-BORN MASHHADI JEWS - GENETIC AND PHYLOGENETIC EVIDENCE FOR COMMON SOURCE OF INFECTION

High prevalence of human T-cell lymphotropic virus type I (HTLV-I) inf ection and disease has been identified among Iranian-born Mashhadi Jew s, an ethnically segregated, highly inbred population. To determine th e origin and genetic diversity of HTLV-I in this group, 1,039 bp spann ing selected regions of the HTLV-I gag, pol env and pX genes were enzy matically amplified and sequenced directly from DNA of five Mashhadi J ews (three with spastic myelopathy and two asymptomatic carriers). Ali gnment and comparison of these sequences with cosmopolitan and Austral o-Melanesian topotypes of HTLV-I indicated that the HTLV-I strains fro m Mashhadi Jews, which were greater than or equal to 99.9% identical a mong themselves, exhibited considerable sequence similarity (greater t han or equal to 99%) to HTLV-I strains from southern India, suggesting a common source of infection. Phylogenetic analysis, using the maximu m parsimony method, was consistent with a single-source introduction o f HTLV-I into the Mashhadi Jewish community. (C) 1995 Wiley-Liss, Inc.