To investigate the variation of porcine reproductive and respiratory syndrome virus(PRRSV) in Hebei Province,samples collected from 12 intensive pig farms suffered with PRRSV from 2004 to 2007 were tested by using RT-PCR.The ORF5 and Nsp2 genes were subjected to PCR amplification,cloning and sequencing by using DNAStar and DNAMAN softwares.The results showed that the amplified ORF5 genes shared from 98.7% to 100% amino acid homology among them,and shared from 88.9% to 100% and from 62.9% to 63.5% amino acid homology with reference strains of North American and Europe genotypes.The amplified Nsp2 genes shared from 82.8% to 100% amino acid homology among them,and shared from 76.5% to 100% amino acid homology with reference strains,respectively.The 6 Nsp2 genes amplified from samples collected from 2006 to 2007 exhibited 30 amino acid deletion(amino acid 482 and amino acid 533 to 561).Phylogenetic analyses showed the Hebei PRRSVs represented North American genotype and belonged to 2 different subgroups,of which,HB0503 was closely related to BJ4,NJ1,HN1,LP1 and VR-2332 strains,and the others were closely related to JXA1,SX and BJ strains.The results suggested that the PRRSVs from the samples collected from 2004 to 2005 were low pathogenic,and the samples collected from 2006 to 2007 were highly pathogenic.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
