陕西关中某羊场羊口疮病毒的分离鉴定与基因序列分析

羊口疮疫病的暴发可严重影响畜牧的经济效益,为探明陕西地区该病的发病原因。本研究从陕西关中地区某羊场出现特征症状病羊嘴部痂皮中分离病原,经过感染MDBK细胞系,获得1株病毒,经形态学、理化学、PCR检测及病理组织学等方法鉴定,该病毒分离株为羊传染性脓疱病毒(Orf virus,ORFV),命名为ORFV-SXGZ。依据GenBank中发表的ORFV特异性B2L、F1L及VIR基因的核酸序列,设计并合成3对引物,应用PCR方法成功对ORFV-SXGZ毒株的B2L、F1L及VIR基因进行克隆,并将其基因序列及推导的氨基酸序列与其他不同来源ORFV分离株进行比较分析。序列分析结果表明,ORFV-SXGZ毒株的B2L、F1L和VIR基因与其他已发表ORFV毒株之间的核苷酸同源性分别为96.7%~99.6%、95.8%~97.9%和95.0%~99.3%,氨基酸同源性分别为95.3%~99.7%、95.8%~98.2%和95.5%~98.4%。系统进化树分析结果显示,ORFV-SXGZ毒株与国内新疆和甘肃等西北部地区分离株的亲缘关系更近,证实陕西关中地区养殖场中存在羊口疮病毒感染。

Isolation and Identification of Orf Virus Shaanxi Guanzhong and Sequence Analysis of B2L, F1L and VIR Genes

The outbreak of Orf can seriously affect the economic benefits of livestock. In order to investigate the etiology of this disease in Shaanxi province, ORFV SXGZ an Orf virus strain was successfully isolated from scab materials of goats with typical clinical symptom through passaging in MDBK cells. This strain was indeed Orf virus, because virus particles form, physico chemical property, PCR products lengths and pathohistology feature were as the same as Orf virus. Three pairs of primers for the B2L, F1L and VIR genes of Orf virus were designed on the basis of published sequences in GenBank. The B2L, F1L and VIR genes of ORFV SXGZ were cloned, and compared nucleotide sequence and the homology of deduced amino acids sequence with other ORFV strains. Compared with other published ORFV strains, the homology of B2L, F1L and VIR genes were 96.7%-99.6%,95.8%-97.9% and 95.0%-99.3%, respectively. The homology of deduced amino acids sequence between ORFV-SXGZ and other strains were 95.3%-99.7%, 95.8%-98.2% and 95.5%-98.4%, respectively. From the three phylogenetic trees, the results showed that ORFV-SXGZ strain was genetically close to other ORFV strains isolated from northwest China. The research confirmed the existence of ORFV infection in Shaanxi Guanzhong area.