Detection and Genetic Characterization of Isolates of Hepatitis E Virus from Pigs and Human in Chungnam Region of Korea

Swine hepatitis E virus (HEV) has been reported as a new zoonotic agent due to its close genomic resemblance to the human HEV. Recently this virus is indicated as one of the important pathogens in xenotransplantation that uses pig as a donor animal. We carried out to investigate the prevalence of HEV infections among the pigs and human population in Chungnam region using a nested RT-PCR for detection of a part of HEV ORF2 gene. The sequences of the amplified DNA were analyzed and the genetical divergency were characterized. A total of 18 HEV strains, comprising 16 strains from pig and 2 strains from human, were genetically isolated from the fecal and serum samples. Among the isolates, 5 strains (2.5%) were detected from 200 swine sera and 2 strains (2.0%) from 100 human sera. All of the 16 swine strains were isolated from the pigs at 3 month of age, but none of age groups revealed the positive for swine HEV RNA. In comparison of the nucleotide sequence between 16 swine HEV and 2 human HEV isolates, the range of identities was 91.5% to 100%. Two human HEV isolates shared 99.7% homology. In phylogenetic analysis, all of the isolates were classified into genotype III, and the 18 isolates were also closely related to the prototype of swine HEV and human HEV strains isolated in the United States and others recently identified from swine in Japan and Netherland.