To investigate the basic characteristics of swine influenza virus (SIV) isolated from Hei Longjiang province,the nasal swabs samples collected from swine farm in Hei Longjiang province in 2007 were inoculated into 10-day-old SPF chicken embryos for virus isolation.Micro-hemagglutination test and RT-PCR amplification for HA and NA genes were conducted to identify the pathogen specificity.Then the amplified HA and NA gene sequences of the isolate were compared with the corresponding gene sequences on GenBank for the homology analysis and the virulence test of the isolate was done by infection experiment with healthy pigs.The results showed that the allantoic fluid infected with nasal swabs samples could agglutinate chicken red blood cell,and the target fragments of H3 and N2 genes were amplified by RT-PCR.Sequence analysis showed that the amplified HA (HM765432) and NA (HM765434) gene sequences both shared 98％ nucleotide homologies similarity with A/swine/Korea/CAS07/2005 (H3N2) (EU798791) and A/swine/Korea/CAS09/2006 (H3N2) (EU798832) published on GenBank.which showed that the isolate belonged to H3N2 subtype SIV.Virulence test revealed that 4 of 5 piglets were infected with the virus and the symptoms were similar to the symptoms of clinically infected pigs.It showed that the isolated virus had a strong pathogenic to pigs,and the isolate could be suitable for evaluating the efficacy of SIV vaccine.%为探究猪流感病毒(SIV)黑龙江分离株的基本特性,本研究将2007年从黑龙江省某猪场采集的鼻拭子样品接种10日龄SPF鸡胚进行病毒分离,经微量血凝试验、HA和NA基因RT-PCR扩增并测序确定其病原特异性,与GenBank已登录的序列进行比对分别分析HA和NA基因序列的同源性,进行动物回归试验确定该分离病毒对猪的致病力.结果显示,接种鼻拭子样品的SPF鸡胚尿囊液有凝集鸡红细胞的活性,经RT-PCR扩增出H3和N2目的基因片段,HA基因序列(HM765432)与A/swine/Korea/CAS07/2005 (H3N2) (EU798791)的HA基因序列同源性为98％,NA基因序列(HM765434)与A/swine/Korea/CAS09/2006(H3N2) (EU798832)的NA基因序列同源性为98％,结果表明分离株为H3N2亚型SIV.动物回归试验结果显示,该分离病毒能够使80％猪发病,且与临床发病猪的症状类似,表明该分离病毒对猪具有较强的致病力,有望成为H3N2亚型SIV疫苗效力评价用效检病毒株.
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