title: Full genome analysis of Philippine indigenous subgenotype IA hepatitis A virus strains from Japanese patients with imported acute hepatitis A.
abstract: OBJECTIVE
  Hepatitis A virus (HAV) is the most common cause of infectious hepatitis worldwide. Although hepatitis A cases imported from South-East Asian countries, including the Philippines, have been reported in Japan, the molecular epidemiological data have been limited for these HAV-endemic countries.
  
  
  METHODS
  The full-length genomic sequences of HAV isolates were determined and subjected to the phylogenetic analyses.
  
  
  RESULTS
  The HAV isolates (HA12-0796 and HA12-0938) obtained from two Japanese patients who developed acute hepatitis A in July 2012, 1 month after traveling to the Philippines, where they consumed undercooked shellfish, differed by only one nucleotide (nt) over the entire genome. These HAV isolates of genotype IA were 99.1-99.5% identical within 228-237 nt to those recovered from river water in the Philippines, suggesting that the HA12-0796 and HA12-0938 isolates represent HAV circulating in the Philippines. HAV isolates belonging to one of the two IA sublineages (IA-2) which were implicated in some of the mini-epidemics in 2010 in Japan are hypothesized to be connected with the Philippines. In support of this speculation, the present IA isolates (HA12-0796 and HA12-0938) shared 98.8% identity over the entire genome with one IA-2 isolate (HAJIH-Fukuo10) recovered from a Japanese female who developed a domestic HAV infection during the mini-epidemics. In the phylogenetic tree constructed based on the entire genome, these three isolates (HA12-0796, HA12-0938 and HAJIH-Fukuo10) segregated into a cluster with a bootstrap value of 100%.
  
  
  CONCLUSIONS
  These results indicate that HAV isolates belonging to the IA-2 lineage might have been imported from the Philippines.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Jichi Medical University School of Medicine, Shimotsuke, Japan.
authors.forename: Shunji
authors.initials: S
authors.lastname: Watanabe
authors.forename: Norio
authors.initials: N
authors.lastname: Isoda
authors.forename: Toshiya
authors.initials: T
authors.lastname: Ohtake
authors.forename: Takuya
authors.initials: T
authors.lastname: Hirosawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Morimoto
authors.forename: Kei
authors.initials: K
authors.lastname: Aoki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohnishi
authors.forename: Masaharu
authors.initials: M
authors.lastname: Takahashi
authors.forename: Kentaro
authors.initials: K
authors.lastname: Sugano
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okamoto
keywords: Philippines; complete genome; hepatitis A; hepatitis A virus; phylogenetic analysis