Tracing the history of hepatitis B virus genotype D in western Japan.
The major hepatitis B virus (HBV) genotypes in Japan are B and C. HBV genotype D (HBV/D), however, is widespread in a small area of Western Japan, where the Gianotti-Crosti syndrome caused by HBV subtype ayw, which is suspected to be HBV/D, was endemic in the 1970s. The aim of the study was to elucidate its origin, time of transmission, and spread in this area. Genotyping of HBV-DNA was done in 363 patients with HBV infection. The year of birth was checked in patients with HBV/D. The full genome sequences of 20 HBV/D strains, 2 of which were obtained from a single carrier with a 19-year-interval, were analyzed. An evolutionary rate, the date of the most recent common ancestor, and the effective number of HBV/D infections were calculated. Fifty-two of 363 patients were infected with HBV/D, and 39 were born in 1970s. In a phylogenetic tree, the 20 HBV/D strains produced a definite cluster, and the evolutionary rate was calculated to be 5.4 x 10(-5) nucleotide substitutions/site/year. The root of the tree was estimated to be in approximately 1,900 and began to spread from the 1940s, leading to a rapid increase of infected patients in the 1970s. From these results, it is suspected that HBV/D was likely transmitted to the area investigated approximately 100 years ago and then spread widely in the 1970s. From the history of the area and the genetic analysis, HBV/D in this area was speculated to be of Russian origin.
Michitaka
Kojiro
K
Third Department of Internal Medicine, Ehime University School of Medicine, Ehime, Japan.
Tanaka
Yasuhito
Y
Horiike
Norio
N
Duong
Tran Nhu
TN
Chen
Yan
Y
Matsuura
Kana
K
Hiasa
Yoichi
Y
Mizokami
Masashi
M
Onji
Morikazu
M
D000169:Acrodermatitis / Q000821:virology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D005260:Female; D005838:Genotype; D006509:Hepatitis B / Q000453:epidemiology / Q000821:virology*; D006515:Hepatitis B virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D009154:Mutation; D010802:Phylogeny; D017422:Sequence Analysis, DNA
D004279:DNA, Viral