title: Characteristics of geographic distributions and route of infection for hepatitis B virus genotype D in Ehime area in western Japan.
abstract: OBJECTIVE
  Hepatitis B virus genotype D (HBV/D) is rare in Japan, and has been shown to circulate in Ehime prefecture in western Japan. HBV/D is suspected to have been transferred into Ehime from Russia as a result of the Japanese-Russian War. This study examined the current geographic spread and infectious route for HBV/D in Ehime.
  
  
  METHODS
  HBV genotype was determined for 508 patients with chronic HBV infection and 46 patients with acute HBV infection hepatitis (acute hepatitis, AH), all of whom were living in Ehime. Ehime was divided into three areas and genotypic distributions were studied.
  
  
  RESULTS
  The ratio of genotypes A,B,C and D in chronically infected patients were 1.8%, 4.5%, 87.8% and 5.9%, respectively. Most patients chronically infected with HBV/D lived in the central area. Only two patients lived in the east and south-west areas, and both had lived in the central area in childhood. Patients with AH due to HBV/D were found only in the central area.
  
  
  CONCLUSIONS
  HBV/D has not yet spread widely to areas other than central Ehime, although small numbers of infected people have moved to other areas. The major infectious route for patients with AH is sexual transmission, regardless of HBV genotype.
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Toon-shi, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Matsuura
authors.forename: Kojiro
authors.initials: K
authors.lastname: Michitaka
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Seijin
authors.initials: S
authors.lastname: Nadano
authors.forename: Shinichi
authors.initials: S
authors.lastname: Okada
authors.forename: Bunzo
authors.initials: B
authors.lastname: Matsuura
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Hiasa
authors.forename: Norio
authors.initials: N
authors.lastname: Horiike
authors.forename: Morikazu
authors.initials: M
authors.lastname: Onji