title: HIV-2 CRF01_AB: first circulating recombinant form of HIV-2.
abstract: BACKGROUND
  Five HIV-2-seropositive cases were recently identified in Japan, outside the HIV-2 endemic area of West Africa. To clarify the molecular epidemiology of HIV-2 in Japan, we analyzed sequences of these cases in detail.
  
  
  METHODS
  HIV-2 genetic groups were determined by gag and env sequences. For suspected recombinant isolates, the genetic structure was determined by full-length genomic analyses. To understand the history and evolution of HIV-2 recombinant isolates, we estimated the time of most recent common ancestor by Bayesian Markov chain Monte Carlo method.
  
  
  RESULTS
  Three isolates were determined as recombinants of groups A and B, and their mosaic genome structures were identical with that of 7312A, a recombinant isolate reported in 1990 from Côte d'Ivoire. Our 3 isolates and 7312A fulfilled the criteria for determining a circulating recombinant form (CRF). These isolates were verified by the Los Alamos HIV sequence database as the first CRF of HIV-2, HIV-2 CRF01_AB. The mean time of most recent common ancestor of CRF01_AB was estimated as between 1964 and 1973, several decades after the estimated emergence of HIV-2.
  
  
  CONCLUSIONS
  We recently identified HIV-2 CRF01_AB cases in Japan. This ectopic observation of the virus outside its original endemic area suggests an ongoing global spread of HIV-2 CRF01_AB.
authors.affiliation: Department of Infection and Immunology, Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Ibe
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Yokomaku
authors.forename: Teiichiro
authors.initials: T
authors.lastname: Shiino
authors.forename: Rie
authors.initials: R
authors.lastname: Tanaka
authors.forename: Junko
authors.initials: J
authors.lastname: Hattori
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Fujisaki
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Iwatani
authors.forename: Naoto
authors.initials: N
authors.lastname: Mamiya
authors.forename: Makoto
authors.initials: M
authors.lastname: Utsumi
authors.forename: Shingo
authors.initials: S
authors.lastname: Kato
authors.forename: Motohiro
authors.initials: M
authors.lastname: Hamaguchi
authors.forename: Wataru
authors.initials: W
authors.lastname: Sugiura
mesh_terms: D000328:Adult; D001483:Base Sequence; D005260:Female; D015967:Gene Expression Regulation, Viral; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology*; D015498:HIV-2 / Q000145:classification / Q000235:genetics*; D054298:Human Immunodeficiency Virus Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016865:Reassortant Viruses; D019562:Viral Load
chemical_list: D054298:Human Immunodeficiency Virus Proteins