Tracing the history of hepatitis B virus genotype D in western Japan

✍ Scribed by Kojiro Michitaka; Yasuhito Tanaka; Norio Horiike; Tran Nhu Duong; Yan Chen; Kana Matsuura; Yoichi Hiasa; Masashi Mizokami; Morikazu Onji

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 153 KB
• Volume: 78
• Category: Article
• ISSN: 0146-6615
• DOI: 10.1002/jmv.20502

✦ Synopsis

Abstract

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 × 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. J. Med. Virol. 78:44–52, 2006. © 2005 Wiley‐Liss, inc.