[Quasispecies investigation on swine hepatitis E viruses].
The objective of current study was to investigate the quasispecies of hepatitis E virus in swine. The partial ORF2 region of HEV envelope gene from four swine HEV strains was amplified by RT-nested polymerase chain reaction (RT-nPCR). After cloning and transformation of PCR products, 20 positive clones of each HEV isolate were subject to sequencing and DNA analysis. The homology among the different clones of each isolates was 96.8%-99.7%, 98.8%-99.7%, 98.8%-99.7% and 100%, respectively, while there was 96.8%-100% sequence identity at the nucleotide level compared with HEV strains isolated in Shanghai (SAAS-JDY5). This study confirmed that there existed quasispecies of HEV in swine.