Molecular epidemiology of HTLV-2 infection among intravenous drug users in Spain

Background: HTLV-2 infection is prevalent among intravenous drug users (IDUs), which often are coinfected with HIV-1. Two main subtypes, HTLV-2a and -2b. have been described among European IDUs, with a characteristically geographic distribution: IIa in northern Europe and IIb in the south. Although frequent traveling within Europe might have favoured a wide dissemination of diverse HTLV-2 variants, HTLV-2b was so far the only subtype reported in Spain. Objective: To investigate the current molecular epidemiology of HTLV-2 in Spain. Study design Twenty-six new HTLV-2 strains isolated from IDUs over the last I I years in different geographic regions were examined. The HTLV LTR regon (620 bp) was sequenced and phylogenetic analyses were performed. Endonuclease restriction sites were examined to further characterize the HTLV-2 subgroup. Results: All 26 individuals infected with HTLV-2 showed viruses belonging to the HTLV-2 b4 clade and were closely related to the previously reported HTLV-2 Spanish and Italian IDU isolates. Conclusions: HTLV-2 Subtype b4 continues to be the only HTLV-2 subgroup recognized so far in Spain and no introduction of other HTLV-2 variants has occurred over the last 11 years. (c) 2004 Elsevier B.V. All rights reserved.