Prevalence of hepatitis E virus (HEV) Infection in wild boars and deer and genetic identification of a genotype 3 HEV from a boar in Japan

Abstract

Zoonotic transmission of hepatitis E virus (HEV) from captured wild deer or boars to humans has been suggested. Antibody to HEV was detected in 9% of 35 wild boars and 2% of 117 wild deer tested, and a presumably indigenous HEV of genotype 3 was isolated from a boar in Japan.

FIG. 1.

Map of Japan showing the locations of Hokkaido Island and 10 prefectures where wild boars and/or deer were captured. The numbers before and after the slash in parentheses indicate the numbers of wild boars and of deer, respectively, examined in the indicated location. The three prefectures in boldface type are the prefectures in which patients with acute hepatitis E who contracted the disease after ingestion of uncooked or undercooked meat or liver from wild boars or deer have been reported (9, 23, 24).

FIG. 2.

Phylogenetic tree constructed by the neighbor-joining method (19) based on the partial nucleotide sequence (298 nt) of the ORF2 region of 56 human, swine, and boar HEV isolates, using an avian HEV (AY535004) as an outgroup. In addition to the wbJSG1 isolate obtained from a viremic boar in the present study, which is boxed for visual clarity, 55 representative human and swine HEV isolates whose common 298-nt sequences are known are included for comparison, and their accession numbers are shown in parentheses. The human, swine, and boar HEV strains isolated in Japan are indicated by boldface type. Asterisks denote swine HEV strains. A cluster consisting of the wbJSG1 strain isolated from a Japanese boar in thepresent study and 18 human and swine HEV strains isolated in Japan is indicated by a vertical bar. Bootstrap values of >70% are indicated for the major nodes as a percentage of the data obtained from 1,000 resamplings (2).