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Molecular characterization of a novel hepatitis E virus (HEV) strain obtained from a wild boar in Japan that is highly divergent from the previously recognized HEV strains
- Takahashi, Masaharu, Nishizawa, Tsutomu, Nagashima, Shigeo, Jirintai, Suljid, Kawakami, Manri, Sonoda, Yoshihide, Suzuki, Tadahiro, Yamamoto, Shogo, Shigemoto, Kazuhiro, Ashida, Kozo, Sato, Yukihiro, Okamoto, Hiroaki
- Virus research 2014 v.180 pp. 59-69
- rabbits, Orthohepevirus A, boars, humans, genome, Herpestidae, nucleotides, phylogeny, Sus scrofa, Chiroptera, ferrets, surveys, wild boars, genotype, genomics, rats, deer, birds, Japan
- Although a consensus classification system for hepatitis E virus (HEV) genotypes is currently unavailable, HEV variants (JBOAR135-Shiz09 and wbJOY_06) from wild boars (Sus scrofa leucomystax) have provisionally been classified into two novel genotypes (5 and 6). While performing a survey of HEV infections among 566 wild boars that were captured in Japan between January 2010 and August 2013, we found 24 boars (4.2%) with ongoing HEV infections: 13 had genotype 3 HEV, 10 had genotype 4 HEV and the remaining boar possessed a novel HEV variant (designated wbJNN_13). The entire wbJNN_13 genome comprised 7247 nucleotides excluding the poly(A) tail, and was highly divergent from known genotype 1 to 4 HEV isolates derived from humans, swine, wild boars, deer, mongoose and rabbits by 22.4–28.2%, JBOAR135-Shiz09 and wbJOY_06 by 19.6−21.9% and rat, ferret, bat and avian HEV isolates by 40.9–46.1% over the entire genome. Phylogenetic trees confirmed that wbJNN_13 is distantly related to all known HEV isolates. A Simplot analysis revealed no significant recombination among the existing HEV strains. These results indicate the presence of at least three genetic lineages of presumably boar-indigenous HEV strains. Further studies to fully understand the extent of the genomic heterogeneity of HEV variants infecting wild boars are warranted.