title: Hepatitis B virus strains of subgenotype A2 with an identical sequence spreading rapidly from the capital region to all over Japan in patients with acute hepatitis B.
abstract: OBJECTIVE
  To examine recent trends of acute infection with hepatitis B virus (HBV) in Japan by nationwide surveillance and phylogenetic analyses.
  
  
  METHODS
  During 1991 through 2009, a sentinel surveillance was conducted in 28 national hospitals in a prospective cohort study. Genotypes of HBV were determined in 547 patients with acute hepatitis B. Nucleotide sequences in the preS1/S2/S gene of genotype A and B isolates were determined for phylogenetic analyses.
  
  
  RESULTS
  HBV genotype A was detected in 137 (25% (accompanied by genotype G in one)) patients, B in 48 (9%), C in 359 (66%), and other genotypes in the remaining three (0.5%). HBV persisted in five with genotype A including the one accompanied by genotype G; another was co-infected with HIV type 1. The genotype was A in 4.8% of patients during 1991-1996, 29.3% during 1997-2002, and 50.0% during 2003-2008 in the capital region, as against 6.5%, 8.5% and 33.1%, respectively, in other regions. Of the 114 genotype A isolates, 13 (11.4%) were subgenotype A1, and 101 (88.6%) were A2, whereas of the 43 genotype B isolates, 10 (23.3%) were subgenotype B1, 28 (65.1%) were B2, two (4.7%) were B3, and three (7.0%) were B4. Sequences of 65 (64%) isolates of A2 were identical, as were three (23%) of A1, and five (18%) of B2, but none of the B1, B3 and B4 isolates shared a sequence.
  
  
  CONCLUSIONS
  Acute infection with HBV of genotype A, subgenotype A2 in particular, appear to be increasing, mainly through sexual contact, and spreading from the capital region to other regions in Japan nationwide. Infection persisted in 4% of the patients with genotype A, and HBV strains with an identical sequence prevailed in subgenotype A2 infections. This study indicates the need for universal vaccination of young people to prevent increases in HBV infection in Japan.
authors: Clinical Research Center, NHO Nagasaki Medical Center, Nagasaki, Japan.
authors: Yoko
authors: Y
authors: Tamada
authors: Hiroshi
authors: H
authors: Yatsuhashi
authors: Naohiko
authors: N
authors: Masaki
authors: Makoto
authors: M
authors: Nakamuta
authors: Eiji
authors: E
authors: Mita
authors: Tatsuji
authors: T
authors: Komatsu
authors: Yukio
authors: Y
authors: Watanabe
authors: Toyokichi
authors: T
authors: Muro
authors: Masaaki
authors: M
authors: Shimada
authors: Taizo
authors: T
authors: Hijioka
authors: Takeaki
authors: T
authors: Satoh
authors: Yutaka
authors: Y
authors: Mano
authors: Toshiki
authors: T
authors: Komeda
authors: Masahiko
authors: M
authors: Takahashi
authors: Hiroshi
authors: H
authors: Kohno
authors: Hajime
authors: H
authors: Ota
authors: Shigeki
authors: S
authors: Hayashi
authors: Yuzo
authors: Y
authors: Miyakawa
authors: Seigo
authors: S
authors: Abiru
authors: Hiromi
authors: H
authors: Ishibashi
mesh_terms: D000208:Acute Disease; D000328:Adult; D004279:DNA, Viral; D005260:Female; D005838:Genotype; D006509:Hepatitis B / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D010802:Phylogeny; D011159:Population Surveillance; D011446:Prospective Studies; D012725:Sexual Behavior
chemical_list: D004279:DNA, Viral