Sporadic acute hepatitis E occurred constantly during the last decade in northeast Japan.
BACKGROUND
Recent studies have shown that indigenous hepatitis E virus (HEV) strains cause hepatitis E in industrialized countries. We aimed to clarify the characteristics of HEV infection in sporadic hepatitis patients during the last decade in Miyagi, northeast Japan.


METHODS
We analyzed 94 serum samples obtained from acute or fulminant hepatitis patients of non-A, non-B, and non-C etiology between 1999 and 2008. Antibody to HEV (anti-HEV) was assayed, and patients who were positive for IgM- and/or IgA-class anti-HEV were diagnosed with hepatitis E. HEV RNA was tested in these patients, and phylogenetic analysis was performed. The occurrence of hepatitis E was compared with that of hepatitis A.


RESULTS
Eight acute hepatitis patients (8.5%) were diagnosed with hepatitis E, and HEV RNA was detectable in seven patients. Five isolates of HEV were segregated into genotype 3 and the remaining two isolates into genotype 4. The year of the occurrence of hepatitis E was distributed almost equally from 1999 to 2008, whereas the cases of acute hepatitis A (n = 16) have decreased markedly in the last several years. In 2004-2008, the occurrence of hepatitis E was greater than that of hepatitis A (five cases vs. one case). As for seasonality, hepatitis E occurred more frequently from September to December than hepatitis A (five cases vs. four cases), although less frequently from January to April (one case vs. seven cases).


CONCLUSIONS
The occurrence of hepatitis E has not decreased during the last decade in northeast Japan, in contrast to hepatitis A.
Inoue
Jun
J
Division of Gastroenterology, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Ueno
Yoshiyuki
Y
Nagasaki
Futoshi
F
Akahane
Takehiro
T
Fukushima
Koji
K
Kogure
Takayuki
T
Kondo
Yasuteru
Y
Kakazu
Eiji
E
Tamai
Keiichi
K
Kido
Osamu
O
Nakagome
Yu
Y
Ninomiya
Masashi
M
Obara
Noriyuki
N
Wakui
Yuta
Y
Takahashi
Masaharu
M
Okamoto
Hiroaki
H
Shimosegawa
Tooru
T
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005838:Genotype; D006506:Hepatitis A / Q000453:epidemiology; D016751:Hepatitis E / Q000453:epidemiology* / Q000276:immunology; D016752:Hepatitis E virus / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000097:blood*; D012621:Seasons; D013997:Time Factors; D055815:Young Adult
D007070:Immunoglobulin A; D007075:Immunoglobulin M; D012367:RNA, Viral