Abstract: The research aimed to study genetic variation and molecular biological characteristics of porcine reproductive and respiratory syndrome virus (PRRSV) from Liaoning hybrid wild boars. A virus strain was isolated by Marc-145 cells from blood of Liaoning hybrid wild boars with suspected porcine reproductive and respiratory syndrome (PRRS) infection. The isolation could induce regular cytopathogenic effects (CPE) on Marc-145 cells after six passages.ORF6 and ORF7 genes of PRRSV isolates were amplified by RT-PCR. The products were sequenced after cloning into pMD18-T vectors respectively. The sequences were analyzed and compared with other PRRSV isolates in GenBank.The results showed that ORF6 and ORF7 genes of the virus isolated shared 96.0% to 100.0%, 94.5% to 99.4%, sequence identities with that of American type strains at home and abroad, at nucleotide level and 89.6% to 100.0%, 87.3% to 98.7% respectively at the amino acid level. However, only 70.4% and 70.1% nucleotide, 48.8% and 49.7% amino acid homologies were found between ORF6, ORF7 genes and Europe type representative strains LV. It indicated that this isolate strain from Liaoning hybrid wild boars belongs to American type PRRSV.

Key words: porcine reproductive and respiratory syndrome virus; isolation; sequence analysis; hybrid wild boars