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AbstractThe province of San Salvador de Jujuy, located in the northwest of Argentina, is a highly endemic area for HTLV-1 infection and a foci of tropical spastic paraparesis/HTLV-1-associated myelopathy (HAM/TSP). Therefore, to better understand this, we carried out a genetic characterization of a large set of HTLV-1 strains (n 65) of descendants of Amerindians from this region. The LTR and envregions were analyzed. The genetic analysis showed that all of these new HTLV-1 isolates from Argentina belong to the Transcontinental subgroup A of the HTLV-1a Cosmopolitan subtype, with the exception of three isolates that cluster within the Japanese subgroup B. Interestingly, the majority of the sequences from Jujuy province belonged to a distinct cluster within the Latin America Transcontinental subgroup, referred to here as the Jujuy subcluster, and were characterized by specific signatures in the LTR. Given that the samples analyzed in this study belong to the Amerindian population and the high prevalence of HTLV-1 in Jujuy in contrast to the low prevalence of this virus in the country, it could be that HTLV-1aA was spread in Argentina from the Amerindians to the cosmopolitan population. Moreover, this is the first report of an HTLV-1aB or Japanese subgroup in descendants of non-Japanese people in South America. [ABSTRACT FROM AUTHOR]

Sequence and cluster analysis have shown two HTLV-1a taxgene subgroups, taxA and taxB, which are related to long terminal repeat (LTR) molecular subtypes. On the basis of subgroup-specific nucleotide substitutions, restriction fragment length polymorphism (RFLP) analysis of the taxgene for subtyping HTLV-1a isolates was proposed. In this study we genetically characterized the taxgene from 63 HTLV-1-positive Argentinean individuals, including 14 patients with HTLV-1-associated myelopathytropical spastic paraparesis and 49 healthy HTLV-1 carriers. RFLP analysis showed that 48 samples yielded the taxA profile (76.19) and that 15 samples contained the uncut taxB profile (23.81). However, the LTR and taxsequence analysis revealed that in fact only 2 from the 15 samples belonged to the HTLV-1aB subgroup, presenting four taxB subgroup-specific nucleotide substitutions. The taxgene cluster analysis also confirmed that the majority of Argentinean strains belonged to the Transcontinental HTLV-1aA subgroup. These results indicate that the taxgene RFLP assay which has been proposed and used by some authors to screen HTLV-1a subgroups, is not a suitable tool to perform molecular epidemiological characterization of HTLV-1a populations. [ABSTRACT FROM AUTHOR]