Molecular epidemiology of human T-cell leukemia virus type I (HTLV-1) Brazil: the predominant HTLV-1s in South America differ from HTLV-ls of Japan and Africa, as well as those of Japanese immigrants and their relatives in Brazil.
To better understand the origin of human T-cell leukemia virus type l (HTLV-l) in South America, we conducted a phylogenetic study on 27 new HTLV-ls in Brazil. These were obtained from Brazilians of various ethnic origins, such as Japanese immigrants, whites, blacks and mulattos. We amplified and sequenced proviral DNAs of a part of the long terminal repeats. Phylogenetic trees revealed that all but 6 of the new isolates were not only similar to each other but also similar to HTLV-ls of other South American countries, including those from Amerindians. However, the isolates differed from the HTLV-ls of Africa and Japan. The other six isolates were from Japanese immigrants and were phylogenetically almost identical to HTLV-ls in Japan but different from the majority of South American HTLV-ls, including the other new Brazilian HTLV-ls. These findings indicate that the recent introduction of HTLV-1 from Japan is limited to Japanese immigrants. In addition, the results do not support the prevailing hypothesis that HTLV-ls in South America were introduced by blacks who were brought from Africa as slaves. Rather, these results suggest that the majority of HTLV-1s prevailing in South America have spread from Amerindians, some of whom are likely to have possessed this human retrovirus from the beginning of their settlement in South America.
Yamashita
M
M
Laboratory of Viral Pathogenesis, Institute for Virus Research Kyoto University, Kyoto, 606-8507, Japan. myamashi@virus.kyuoto-u.ac.jp
Veronesi
R
R
Menna-Barreto
M
M
Harrington
W J
WJ
Sampio
C
C
Brites
C
C
Badaro
R
R
Andrade-Filho
A S
AS
Okhura
S
S
Igarashi
T
T
Takehisa
J
J
Miura
T
T
Chamone
D
D
Bianchini
O
O
Jardim
C
C
Sonoda
S
S
Hayami
M
M
D000328:Adult; D000349:Africa; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D001938:Brazil / Q000453:epidemiology; D004641:Emigration and Immigration; D005006:Ethnicity; D005260:Female; D015490:HTLV-I Infections / Q000453:epidemiology* / Q000821:virology*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007564:Japan / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D020079:Terminal Repeat Sequences / Q000235:genetics