title: Epidemiological and genetic analysis of a 2014 outbreak of hepatitis A in Japan.
abstract: Hepatitis A virus (HAV) is one of the most common causes of feces-transmitted acute hepatitis worldwide. In Japan, most of HAV infections have been sporadic cases and a relatively low number of cases (approximately 100-150) of acute hepatitis A were reported in 2012 and 2013. However, in 2014, 342 cases were reported as of week 22. In order to characterize the viral agents causing this outbreak, we collected stool or sera (and both for three case) from patients with hepatitis A from many regions throughout Japan and performed genotyping of the VP1/P2A regions of HAV. We then used a multiple-alignment algorithm to compare the nucleotide sequences with those of reference strains. Phylogenetic tree analyses revealed that the 159 HAV isolates were divided into three subgenotypes: IA (137 cases), IB (4 cases), and IIIA (18 cases). The most unique feature of this outbreak was that for most subgenotype IA cases (103 out of 137 IA cases) the sequences analyzed shared 100% homology. Interestingly, the peak week for these IA infections was almost the same nationwide, suggesting that the epidemic of hepatitis A caused by this subgenotype IA strain may have expanded from a single source possibly because of one food-borne or waterborne source that was distributed nationwide at once.
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan. Electronic address: kishii@nih.go.jp.
authors.forename: Koji
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kiyohara
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Yoshizaki
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Kawabata
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kanayama
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Yahata
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Takuri
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kinoshita
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Saitou
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tomimasa
authors.initials: T
authors.lastname: Sunagawa
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Oishi
authors.affiliation: Division of Biomedical Food Research, National Institute of Health Sciences, Tokyo, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Uema
authors.affiliation: Division of Biomedical Food Research, National Institute of Health Sciences, Tokyo, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Noda
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Takaji
authors.initials: T
authors.lastname: Wakita
mesh_terms: D000328:Adult; D000368:Aged; D001483:Base Sequence; D001769:Blood / Q000821:virology; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D005243:Feces / Q000821:virology; D005260:Female; D005838:Genotype; D006506:Hepatitis A / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D030041:Hepatitis A virus / Q000145:classification / Q000235:genetics*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D015678:Viral Structural Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; C096539:VP1 protein, hepatitis A virus; D015678:Viral Structural Proteins
keywords: Genotype; Hepatitis A virus; Outbreak; Phylogenetic analysis