Prevalence and genotyping of hepatitis E virus in swine population in Korea between 1995 and 2004: a retrospective study

Hepatitis E virus (HEV) infections have been reported in pigs throughout the world but have only recently been recorded in Korean pigs. The aim of this study was to investigate whether HEV was present in archived porcine hepatic tissues collected between 1995 and 2004 using RT-PCR and immunohistochemistry and, if so, to determine the genotype of the isolates. Swine HEV was identified in the liver tissue of 42 pigs of 388 submissions (four pigs every year on average). The isolates showed genetic homology with swine and human HEV isolates identified in the United States and Japan (92.5-97%) and phylogenetic tree analysis indicated they belonged to genotype III. The study indicates that HEV is not a newly emerging virus in Korean pigs, but a pathogen that has existed in the country since at least 1995.