Prevalence of hepatitis E virus among wild boar in the Ehime area of western Japan.
OBJECTIVE
Transmission of hepatitis E virus (HEV) from wild boar to humans has been reported, particularly from Japan. We attempted to clarify this issue.


METHODS
We assessed the IgG class antibodies against HEV (anti-HEV) in serum samples taken from 406 boar living in the Ehime area of western Japan from 2001 to 2004, of which 392 were captured in the wild (wild-caught boar) and 14 had been kept in a breeding farm (bred boar).


RESULTS
Anti-HEV positive rate in the bred boar (10/14, 71.4%) was significantly higher than in the wild-caught boar (100/392, 25.5%) (P < 0.001). Of the 392 wild-caught boar, 12 (3.1%) were positive for HEV-RNA, 10 of which were then subjected to phylogenetic analyses by sequencing an 821-nt fragment within ORF1. All the 10 isolates segregated to genotype 3, and eight of them were mutually related to form a cluster. All the eight HEV isolates in this cluster were from the wild-caught boar living in one and the same habitat within the studied area, while the other two independent isolates were from different regions.


CONCLUSIONS
HEV infection is endemic in wild boar in the Ehime area, and we should regard the wild boar as an important reservoir of HEV.
Michitaka
Kojiro
K
Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Ehime, Japan.
Takahashi
Kazuaki
K
Furukawa
Shinya
S
Inoue
Gaku
G
Hiasa
Yoichi
Y
Horiike
Norio
N
Onji
Morikazu
M
Abe
Natsumi
N
Mishiro
Shunji
S