关键词: 猪繁殖与呼吸综合征病毒; 分离; 遗传变异; ORF5基因; Nsp2基因

Abstract: To study the genetic variation of porcine reproductive and respiratory syndrome virus(PRRSV)in Shandong, Henan and Hebei province of China, 42 samples from pig farms in three provinces were isolated and identified during 2006 to 2012. 15 PRRSV isolates were successfully isolated, identified by PCR and biological characteristics were studied. The complete ORF5 and partial Nsp2 genes of 15 isolates were amplified and sequenced. The deduced amino acid sequences were blasted with deduced sequences of 68 ORF5 genes and 40 Nsp2 genes in GenBank. The analysis showed that all 15 isolates belonged to American groups, 13 of them presented discontinuous amino acid deletions in Nsp2, and the homology of ORF5 deduced amino acid sequences with JXA1 were from 95.5% to 97.5%. Besides, isolate SDDY2007 showed higher similarity to vaccine strain RespPRRSV MLV(98.5%), which was located in America subgroupⅡ. A more interesting thing was that, though Nsp2 sequence of HN25-2009 contained 30 amino acids deletion, its deduced amino acid sequences showed higher similarity to VR2332(97.5%). In short, highly pathogenic PRRSV was the dominant PRRSV in Shandong, Henan and Hebei during 2006 to 2012. Although there were some genetic variations among PRRSV isolates in three provinces, no obvious regional characteristics could be found.

Key words: porcine reproductive and respiratory syndrome virus; isolation; genetic diversity; ORF5 gene; Nsp2 gene