HTLV-I But not HTLV-II infection among Amerindians in French Guiana: seroepidemiological study and phylogenetic characterization

Abstract

P109 While HTLV-I infection in the Creole and Noir-Marron populations of French Guiana is well documented, there are no data concerning the HTLV-I/II infection among Amerindians living in this area. We therefore investigated the serological, epidemiological and molecular aspects of HTLV-I and HTLV-II infections among Amerindians living in French Guiana. Serological status using ELISA and western blot, was established for 847 sera (302 men and 545 women). No HTLV-II antibodies were detected but five individuals (0.59%) were HTLV-I seropositive. A 522 bp portion of the gp 21 of the env gene and a 424 bp portion of the HTLV-I LTR were sequenced for these 4 amerindians, and for 5 creoles and 5 Noirs-marrons. To confirm the genomic subtype of the HTLV-I strains, the complete LTR (755 bp) was sequenced in one member of each ethnic group. Nucleotide sequences analysis showed that all strains from French Guiana were very similar to the cosmopolitan subtype A prototype ATK strain. Nucleotide similarities were more important between Amerindian and Creole strains (98.9 to 99.8 similar) than between Amerindian and Noir-marron strains (98.3 to 99.3) or than between Creole and Noir-Marron strains (98.1 to 99.4). The phylogenetic analysis identified two clusters, one was made of the strains from Amerindians and Creoles which belong to the Transcontinental subgroup, and the second cluster was made of the strains from Noir-Marrons belonging to the West African subgroup. The results of the phylogenetic analysis demonstrate that HTLV-I infection was recently introduced in Amerindians in this area and that Amerindian HTLV-I strains are of African origin.