Emerging Infectious Diseases (May 2009)

Virulent Strain of Hepatitis E Virus Genotype 3, Japan

  • Kazuaki Takahashi,
  • Hiroaki Okamoto,
  • Natsumi Abe,
  • Manri Kawakami,
  • Hiroyuki Matsuda,
  • Satoshi Mochida,
  • Hiroshi Sakugawa,
  • Yoshiki Suginoshita,
  • Seishiro Watanabe,
  • Kazuhide Yamamoto,
  • Yuzo Miyakawa,
  • Shunji Mishiro

DOI
https://doi.org/10.3201/eid1505.081100
Journal volume & issue
Vol. 15, no. 5
pp. 704 – 709

Abstract

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Hepatitis E virus (HEV) genotype 3, which usually causes asymptomatic infection in Japan, induced severe hepatitis in 8 patients. To better understand genetic features of HEV associated with increased virulence, we determined the complete or near-complete nucleotide sequences of HEV from these 8 patients and from 5 swine infected with genotype 3 strain swJ19. Phylogenetic analysis showed that the isolates from the 8 patients and the 5 swine grouped separately from the other genotype 3 isolates to create a unique cluster, designated JIO. The human JIO-related viruses encoded 18 amino acids different from those of the other HEV genotype 3 strains. One substitution common to almost all human HEV strains in the JIO cluster was located in the helicase domain (V239A) and may be associated with increased virulence. A zoonotic origin of JIO-related viruses is suspected because the isolates from the 5 swine also possessed the signature V239A substitution in helicase.

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