猪流行性腹泻病毒YT1401株分离鉴定及分子进化分析

Isolation,identification and phylogenetic analysis of a porcine epidemic diarrhea virus strain YT1401

猪流行性腹泻病毒(PEDV)是一种引起猪腹泻的病原体,但由于引发该病的病原体众多、病因复杂,仅通过临床症状和病理组织学变化并不能对PEDV确诊,本研究参考40株PEDV基因设计了1对能高效扩增该N基因片段的引物,建立了PEDV分子诊断方法。并采用该方法从山东烟台某猪场的腹泻样本中检测获得了1株PEDV,采用分段重叠策略扩增获得了该毒株全基因序列,并在此基础上分析了该毒株全基因序列以及S基因的遗传进化关系。所有分析结果均表明,本研究分离获得的PEDV毒株与经典毒株比较发生了重大变化,为新的变异株。该结果提示我们,采用PEDV经典毒株或是早年分离的毒株制作的疫苗并不能有效防控当前流行的PED,研制以当前流行毒株为背景研制新型PEDV疫苗势在必行。

Porcine epidemic diarrhea virus （PEDV） is one of the pathogens causing swine diarrhea. However,it is very hard to diagnose PEDV through clinical symptom and pathological changes due to complexity and numbers of pathogens causing diarrhea. A pair of PCR primers specific to nucleoprotein gene was designed according to alignment of 40 PEDV strains. A molecular diagnostic method for PEDV detection was developed using this primer set. With this method,a new PEDV strain was found from the diarrhea specimens collected from a pig farm located in Yantai, Shan- dong province. Lately, the whole genome was amplified by overlapped RT-PCR and subjected to phylogenetic analysis. The S gene and spike protein was also analyzed. All results demonstrated that this newly isolated PEDV strain had significant variations comparing to classic strains and was an epidemic PEDV strain. These results indicated that the vaccines developed from the classic PEDV strains may not work for the prevention and control of current epidemics of PED and new vaccines based on the epidemic PEDV strains is imperative.