title: The close relationship between South African and Latin American HTLV type 1 strains corroborated in a molecular epidemiological study of the HTLV type 1 isolates from a blood donor cohort.
abstract: It has been difficult to explain why all HTLV-1 sequences in Salvador, a city in the northeast of Brazil, belong to the Transcontinental (A) subgroup of the Cosmopolitan (a) subtype, since according to historical data the vast majority of slaves brought to Brazil (through Salvador) came from west Africa, where only the western African subgroup (C) has been found. To shed more light on this subject we conducted a phylogenetic analysis of 23 isolates from blood donors of Salvador. DNA was extracted and submitted to a nested PCR for amplification of the entire LTR region. The PCR products were purified and sequenced on an automated sequencer. Neighbor-joining and maximum likelihood phylogenetic analyses were performed. None of the new sequences from Salvador clustered within the West-African subgroup C. Confirming previous results, all sequences belonged to the Transcontinental subgroup (A) of the Cosmopolitan subtype, and clustered in two Latin American clusters. In addition we showed sequences from southern Africa clustering in both Latin American clusters. One of the new sequences is ancestral to the larger Latin American cluster beta due to a duplication of a 12-bp long fragment, a finding that has not been previously described. These findings support the hypothesis that HTLV-1 isolates circulating in Latin America have a closer relationship to South African compared to West-African HTLV-1 strains. The 12-bp-long duplications in one of the sequences has no obvious clinical or biological implications yet.
authors.affiliation: Bahia School of Medicine and Public Health/Foundation for Scientific Development, Rua Waldemar Falcao 121, Brotas, Salvador, Bahia 40295-001, Brazil. lalcan@cpqgm.fiocruz.br
authors.forename: Augusto Cesar Andrade
authors.initials: AC
authors.lastname: Mota
authors.forename: Sonia
authors.initials: S
authors.lastname: Van Dooren
authors.forename: Flora Maria de Campos
authors.initials: FM
authors.lastname: Fernandes
authors.forename: Sergio Araujo
authors.initials: SA
authors.lastname: Pereira
authors.forename: Artur Trancoso Lopo
authors.initials: AT
authors.lastname: Queiroz
authors.forename: Viviana Olavarria
authors.initials: VO
authors.lastname: Gallazzi
authors.forename: Anne-Mieke
authors.initials: AM
authors.lastname: Vandamme
authors.forename: Bernardo
authors.initials: B
authors.lastname: Galvão-Castro
authors.forename: Luiz Carlos Junior
authors.initials: LC
authors.lastname: Alcantara
mesh_terms: D001782:Blood Donors; D001938:Brazil / Q000453:epidemiology; D015331:Cohort Studies; D015490:HTLV-I Infections / Q000453:epidemiology* / Q000208:ethnology* / Q000235:genetics; D015368:Human T-lymphotropic virus 1 / Q000145:classification* / Q000235:genetics; D006801:Humans; D008877:Middle East / Q000453:epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D013019:South Africa / Q000453:epidemiology / Q000208:ethnology