title: A nationwide survey of hepatitis E virus infection in the general population of Japan.
abstract: To investigate nationwide the prevalence of hepatitis E virus (HEV) infection in the general population of Japan, serum samples were collected from 22,027 individuals (9,686 males and 12,341 females; age, mean +/- standard deviation: 56.8 +/- 16.7 years; range: 20-108 years) who lived in 30 prefectures located in Hokkaido, mainland Honshu, Shikoku, and Kyushu of Japan and underwent health check-ups during 2002-2007, and were tested for the presence of IgG, IgM, and IgA classes of antibodies to HEV (anti-HEV) by in-house ELISA and HEV RNA by nested RT-PCR. Overall, 1,167 individuals (5.3%) were positive for anti-HEV IgG, including 753 males (7.8%) and 414 females (3.4%), the difference being statistically significant (P < 0.0001). The prevalence of anti-HEV IgG generally increased with age and was significantly higher among individuals aged >or=50 years than among those aged <50 years (6.6% vs. 2.7%, P < 0.0001). Although 13 individuals with anti-HEV IgG also had anti-HEV IgM and/or anti-HEV IgA, none of them had detectable HEV RNA. The presence of HEV RNA was further tested in 50 or 49-sample minipools of sera from the remaining 22,014 individuals, and three individuals without anti-HEV antibodies tested positive for HEV RNA. The HEV isolates obtained from the three viremic individuals segregated into genotype 3 and were closest to Japan-indigenous HEV strains. When stratified by geographic region, the prevalence of anti-HEV IgG as well as the prevalence of HEV RNA or anti-HEV IgM and/or anti-HEV IgA was significantly higher in northern Japan than in southern Japan (6.7% vs. 3.2%, P < 0.0001; 0.11% vs. 0.01%, P = 0.0056; respectively).
authors.affiliation: Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi-Ken, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Takahashi
authors.forename: Kazuko
authors.initials: K
authors.lastname: Tamura
authors.forename: Yu
authors.initials: Y
authors.lastname: Hoshino
authors.forename: Shigeo
authors.initials: S
authors.lastname: Nagashima
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yazaki
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Mizuo
authors.forename: Sadahiko
authors.initials: S
authors.lastname: Iwamoto
authors.forename: Masanobu
authors.initials: M
authors.lastname: Okayama
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Eiji
authors.initials: E
authors.lastname: Kajii
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okamoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D016000:Cluster Analysis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005838:Genotype; D016751:Hepatitis E / Q000453:epidemiology* / Q000821:virology*; D016752:Hepatitis E virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D015995:Prevalence; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012367:RNA, Viral