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  • Meeting abstract
  • Open Access

Human T-Lymphotropic Virus Type 1 (Htlv-1): a new subgroup within the cosmopolitan subtype

  • 1,
  • 2,
  • 1,
  • 1,
  • 1 and
  • 1Email author
Retrovirology20118 (Suppl 1) :A75

  • Published:


  • Nucleotide
  • Infectious Disease
  • Cancer Research
  • Virus Type
  • Specific Region


HTLV-1 is classified in seven subtypes (a-g) most of them restricted to specific regions (b-e), while the Cosmopolitan subtype (a) is worldwide distributed. Cosmopolitan subtype has experimented a degree of molecular diversity giving rise to five subgroups: Transcontinental (A), Japanese (B), West African (C), North African (D) and Black Peruvian (E).


to confirm the classification of four HTLV-1 highly divergent strains as a new subgroup within the Cosmopolitan subtype.

Materials and methods

LTR sequences from 65 HTLV-1 positive Buenos Aires residents were retrospectively studied. Phylogeny of LTR region was studied by three different methods (ML, MP and NJ). A similitude index (SI) was estimated as the mean number of nucleotide substitutions from each subgroup (intra-subgroup) or between sequences from a given subgroup against all from other subgroups (inter-subgroup) (script described in the R Statistical Package Language


The three phylogenetic methods were consistent, showing a well supported monophyletic clade that included two Peruvian sequences clustering with two references (Bl3 from Peru and Br4 from Brazil) previously described as divergent, branching off all known subgroups (82% bootstrap, ML). The similitude analysis showed a SI intra-subgroup similar to those obtained for A-D subgroups and a SI inter-subgroup similar to subgroups A and D. Following nomenclature, it was named subgroup F.


This study confirms the existence of a highly divergent monophyletic clade within the Cosmopolitan subtype composed of sequences from Peruvian and Brazilian individuals and suggest that more studies should be performed in this South-American area where the last subgroups (E and F) has been detected.

Authors’ Affiliations

Facultad de Medicina, UBA, Centro Nacional de Referencia para el SIDA, Buenos Aires, Argentina
División de Biología Molecular, Estación de Fotobiología Playa Unión, Playa Unión, Chubut, Argentina


© Eirin et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.