Epidemiological and clinical study of sporadic acute hepatitis E caused by indigenous strains of hepatitis E virus in Japan compared with acute hepatitis A.
BACKGROUND
We compared acute hepatitis E (AH-E) and acute hepatitis A (AH-A) to investigate the epidemiology, clinical features, and prognosis of AH-E caused by an indigenous hepatitis E virus (HEV) in Japan.


METHODS
We enrolled 58 patients diagnosed with AH-A or AH-E (32 men and 26 women; age, 20-72 years) from December 1997 to October 2002. Phylogenetic analysis of the partial 412-nucleotide sequence of open reading frame (ORF) 2 was performed in patients with AH-E.


RESULTS
Regarding the geographic distribution of the HEV genotype, genotype III was principally distributed in Honshu Island, and genotype IV in Hokkaido Island ( P = 0.0034). The phylogenetic analysis of the ORF2 region revealed that there were significant geographic differences in the distribution of the HEV strains in Japan, with some strains being widespread and some, localized. In comparison with AH-A patients, those with AH-E were older (56.1 +/- 10.6 vs 45.9 +/- 10.8 years; P = 0.0017). The proportion of males among patients with AH-E was significantly higher ( P = 0.0001). Pyrexia was often observed in AH-A, and malaise in AH-E. Laboratory data indicate that AH-E induces a weak immunological reaction, whereas jaundice appears earlier in AH-E than in AH-A. One patient with AH-E died of acute hepatic failure, but none of those with AH-A died during the study period.


CONCLUSIONS
Our results suggest that there are geographical differences between HEV strains in Japan, and that AH-E is more common in males and older patients than AH-A. Laboratory data indicate a weak immunological reaction and early appearance of jaundice in AH-E.
Sainokami
Shigehiko
S
First Department of Internal Medicine, Iwate Medical University, Morioka, Japan.
Abe
Koichi
K
Kumagai
Ichiro
I
Miyasaka
Akio
A
Endo
Ryujin
R
Takikawa
Yasuhiro
Y
Suzuki
Kazuyuki
K
Mizuo
Hitoshi
H
Sugai
Yoshiki
Y
Akahane
Yoshihiro
Y
Koizumi
Yoichi
Y
Yajima
Yoshiaki
Y
Okamoto
Hiroaki
H
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D005260:Female; D005838:Genotype; D006506:Hepatitis A / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D016751:Hepatitis E / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology*; D016752:Hepatitis E virus / Q000145:classification* / Q000235:genetics / Q000276:immunology; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012367:RNA, Viral / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014764:Viral Proteins / Q000235:genetics
D000914:Antibodies, Viral; C400971:ORF2 protein, Hepatitis E virus; D012367:RNA, Viral; D014764:Viral Proteins