TY - JOUR T1 - 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 JF - Gut JO - Gut DO - 10.1136/gutjnl-2011-300832 SP - gutjnl-2011-300832 AU - Yoko Tamada AU - Hiroshi Yatsuhashi AU - Naohiko Masaki AU - Makoto Nakamuta AU - Eiji Mita AU - Tatsuji Komatsu AU - Yukio Watanabe AU - Toyokichi Muro AU - Masaaki Shimada AU - Taizo Hijioka AU - Takeaki Satoh AU - Yutaka Mano AU - Toshiki Komeda AU - Masahiko Takahashi AU - Hiroshi Kohno AU - Hajime Ota AU - Shigeki Hayashi AU - Yuzo Miyakawa AU - Seigo Abiru AU - Hiromi Ishibashi Y1 - 2011/01/01 UR - http://gut.bmj.com/content/early/2011/11/07/gutjnl-2011-300832.abstract N2 - 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. ER -