A novel virus in swine is closely related to the human hepatitis E virus

Abstract

A novel virus, designated swine hepatitis E virus (swine HEV), was identified in pigs. Swine HEV crossreacts with antibody to the human HEV capsid antigen. Swine HEV is a ubiquitous agent and the majority of swine >3 months of age in herds from the midwestern United States were seropositive. Young pigs naturally infected by swine HEV were clinically normal but had microscopic evidence of hepatitis, and developed viremia prior to seroconversion. The entire ORFs 2 and 3 were amplified by reverse transcription-PCR from sera of naturally infected pigs. The putative capsid gene (ORF2) of swine HEV shared about 79-80% sequence identity at the nucleotide level and 90-92% identity at the amino acid level with human HEV strains. The small ORF3 of swine HEV had 83-85% nucleotide sequence identity and 77-82% amino acid identity with human HEV strains. Phylogenetic analyses showed that swine HEV is closely related to, but distinct from, human HEV strains. The discovery of swine HEV not only has implications for HEV vaccine development, diagnosis, and biology, but also raises a potential public health concern for zoonosis or xenozoonosis following xenotransplantation with pig organs.

The Leu477 and Leu613 of ORF2-Encoded Protein Are Critical in Forming Neutralization Antigenic Epitope of Hepatitis E Virus Genotype 4

“…The Leu477 and Leu613 appeared highly conservative even in the avian HEV ORF2 encoded protein, which shares only 48-49% amino acid sequence identities with other known HEV strains (37). This remarkable conservation implied that Leu477 and Leu613 might play key roles in the formation of the neutralization epitope among different HEV isolates and support the observation that HEV only has one serotype (38,39).…”

Hepatitis E in Norway: seroprevalence in humans and swine

“…For further characterization and comparison, the open reading frame 2 (ORF2) region of HEV RNA of all PCR-positive specimens was sequenced as previously described [14]. A two-step nested RT-PCR using SuperScript III (Life Technologies, USA) and Platinum Quantitative PCR SuperMix-UDG (Life Technologies) was used for sequencing of the capsid gene.…”

Transmission routes and risk factors for autochthonous hepatitis E virus infection in Europe: a systematic review

“…In 1997, HEV gt3 strains were detected in swine in the USA [14]. HEV gt3 and gt4 have since been found to be endemic in pig herds worldwide [15,16].…”