Molecular Evidence of HTLV-II Subtype B Among an Urban Population Living in South Brazil

Abstract

Human T cell lymphotropic virus type II (HTLV-II) is a deltaretrovirus endemic in Indian populations living in Central and South America, among Pygmies tribes from Central Africa, and epidemic among injecting drug users (IDUs) in the United States, Europe, Southeast Asia, and South America. To date only the HTLV-IIa subtype has been demonstrated among Brazilians (Amazon basin Indians, blood donors, and IDUs). We analyzed HTLV-II isolates from 12 individuals living in the urban area of Porto Alegre, Southern Brazil, identified as seropositive for HTLVI/II in a blood donation. The HTLV-II long terminal repeat (LTR) region was sequenced and compared with nucleotide sequences of isolates HTLV-IIa (Mo), HTLV-IIb (NRA) prototypes. Phylogenetic analysis of the LTR region demonstrated that seven new isolates clustered together with American Indians HTLV-IIb isolates, and five new HTLV-IIa isolates clustered within the HTLV-IIa Brazilian subgroup, named the HTLV-IIc subtype. Both HTLV-IIa and IIb seem to be endemic in the urban area of Porto Alegre, South of Brazil, and could have reached this region via the Amazon basin and the Pacific Coast ancient human migratory pathways. To our knowledge this is the first study demonstrating the presence of HTLV-IIb among the urban population in Brazil.

Human T Cell Lymphotropic Virus Type 2a Strains Among HIV Type 1-Coinfected Patients from Brazil Have Originated Mostly from Brazilian Amerindians

“…Consistent with this finding, the HTLV-2b subtype has been found in the state of Rio Grande do Sul in Brazil, 20 bordering countries where the HTLV-2b subtype prevails. We could speculate that with the commercial agreement of Mercosul, the increasing population flux across borders warrants monitoring this viral subtype in the country.…”

“…7 Therefore, HTLV-2 molecular characterization worldwide disclosed four HTLV subtypes: HTLV-2a and HTLV-2b, the most prevalent among IDUs from urban areas of the Americas and Europe and in the indigenous population of the Americas, and with sporadic distribution in Asia and Africa; the HTLV-2c variant detected in the indigenous population of the Brazilian Amazon and in IDUs from urban populations in Brazil; and the HTLV-2d detected in pygmy tribes in Africa. 13,[16][17][18][19][20][21] In 2010, we started the characterization of HTLV-2 isolates that circulate in HIV-coinfected individuals from southern Brazil using nucleotide sequence and restriction fragment length polymorphism (RFLP) analysis of the LTR region, and confirmed that all HTLV-2 strains belonging to the 2a subtype. Moreover, we observed an association of molecular variants and sexual risk factor and injecting drug use.…”

Caracterização molecular do HTLV-1/2 em doadores de sangue em Belém, Estado do Pará: primeira descrição do subtipo HTLV-2b na região Amazônica

“…A presença deste subtipo no Brasil foi recentemente descrita entre doadores de sangue em Porto Alegre (RS), sendo atribuída à migração a partir da fronteira com a Argentina 25 .…”

The challenge of describing the epidemiology of HTLV in the Amazon region of Brazil

“…The history of HTLV is a fascinating one regarding its possible origin in the African continent and its spread in different directions according to human migration routes [4], and the ARB is of paramount importance because of the presence of a specific strain of the virus that originated during human migration into the area and its further dissemination to other geographical areas in the country and abroad [36,51,[91][92][93][94][95][96][97].…”