title: Molecular epidemiology of human T-lymphotropic virus type II infection in Amerindian and urban populations of the Amazon region of Brazil.
abstract: Molecular characterization of human T-cell lymphotropic virus II (HTLV-II) isolates in North America and Europe has shown the existence of two principal subtypes of the virus, HTLV-IIa and HTLV-IIb. Subsequent studies on HTLV-II isolates from Brazil have suggested the existence of a unique variant phylogenetically related to HTLV-IIa but phenotypically similar to HTLV-IIb with respect to the transactivatory protein, Tax. This variant has been designated HTLV-IIc. To better clarify the variability and distribution of HTLV-II in Brazil, the viruses present in two population groups from the Amazon region were tested for the presence of HTLV-II using serological and molecular assays. The groups consisted of blood donors from three Amerindian communities and of HIV-1/HTLV-II coinfected patients residing in Belém, an urban area. Nucleotide sequences and phylogenetic analysis confirmed the presence of HTLV-IIc subtype among Amerindian populations and, for the first time, the presence of the same virus among urban groups in Belém. The isolated occurrence of the HTLV-IIc subtype among Amerindian populations in the Amazon region could be attributed to (1) the different migratory pathways and founder effect, or (2) the local origin of a proto-HTLV-II carried by Amerindian ancestors who migrated to the Amazon circa 11,000 to 13,000 years ago. These results suggest that not only is HTLV-IIc unique to this region, but that its presence in urban areas of Brazil has resulted from admixture processes during the colonization of the country.
authors.affiliation: Laboratório de Virologia, Centro de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Antonio C R
authors.initials: AC
authors.lastname: Vallinoto
authors.forename: Marluísa O G
authors.initials: MO
authors.lastname: Ishak
authors.forename: Vânia N
authors.initials: VN
authors.lastname: Azevedo
authors.forename: Ana Carolina P
authors.initials: AC
authors.lastname: Vicente
authors.forename: Koko
authors.initials: K
authors.lastname: Otsuki
authors.forename: William W
authors.initials: WW
authors.lastname: Hall
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ishak
mesh_terms: D001483:Base Sequence / Q000235:genetics; D001782:Blood Donors / Q000706:statistics & numerical data; D001938:Brazil / Q000453:epidemiology; D018595:Colonialism; D004641:Emigration and Immigration / Q000706:statistics & numerical data; D019353:Endemic Diseases / Q000706:statistics & numerical data; D019143:Evolution, Molecular; D018703:Founder Effect; D015658:HIV Infections / Q000150:complications / Q000453:epidemiology / Q000821:virology; D015491:HTLV-II Infections / Q000150:complications / Q000453:epidemiology* / Q000821:virology*; D015368:Human T-lymphotropic virus 1 / Q000145:classification / Q000235:genetics*; D015367:Human T-lymphotropic virus 2 / Q000145:classification / Q000235:genetics*; D006801:Humans; D007199:Indians, South American / Q000706:statistics & numerical data*; D017720:Molecular Epidemiology; D010641:Phenotype; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011159:Population Surveillance; D014505:Urban Population / Q000706:statistics & numerical data*