浙江及周边地区猪流行性腹泻病毒S基因分子特征分析

对2013 年4 月至2017 年4 月间浙江省及周边24 个地区共282 份病料进行猪流行性腹泻病毒（porcine epidemic diarrhea virus, PEDV）、轮状病毒A型（porcine groupArotavirus, GARV）、猪δ冠状病毒（porcine deltacoronavirus, PDCoV）和猪传染性胃肠炎病毒（porcine transmissible gastroenteritis virus, TGEV）等病原的检测，并选取其中的16份PEDV阳性样品进行S基因克隆和序列分析。结果显示：PEDV的检出率为64.89%（183/282），GARV为0.35%（1/282），PDCoV为4.25%（12/282），而未检出TGEV；PEDV在11月1 日至次年4 月1 日间的累计检出率为74%，其余时间段的累计检出率为26%。对PEDV的S蛋白进行分子演化分析表明，PEDV可分为3 个群，其中16 份阳性样品均位于Ⅲ群，与疫苗毒株CV777、SM98 和DR13 株相比，核苷酸同源性为93.6%～95.2%，氨基酸同源性为92.4%～94.9%。16 份PEDV阳性样品与中国PEDV的CV777疫苗毒株相比，形成了3个新的N-糖基化位点，破坏了1个N-糖基化位点。综上表明，当前仔猪腹泻主要病原为PEDV变异株，防控猪流行性腹泻需要注意季节的变化，也需要加快流行株疫苗的开发。 通讯作者: 李肖梁（https://orcid.org/0000-0002-2058-7764） E-mail: xlli@zju.edu.cn
Abstract: We carried out pathogen detection of 282 clinical samples collected from Zhejiang Province and its 24 surrounding areas during April 2013 to April 2017. Among them, 16 positive samples were selected for S gene cloning and sequencing. The results showed that the detection rate of porcine epidemic diarrhea virus (PEDV), porcine group A rotavirus (GARV), porcine deltacoronavirus (PDCoV) and porcine transmissible gastroenteritis virus (TGEV) was 64.89% (183/282), 0.35% (1/282), 4.25% (12/282) and 0% (0/282), respectively. During November 1st to April 1st of the next year, the detection rate of PEDV was 74%, which was 26% in the remaining time. PEDV can be divided into three groups by molecular evolution analysis based on spike (S) protein. All of the 16 positive samples were located in the group Ⅲ. Compared with vaccine strains CV777, SM98, and DR13, the PEDV positive samples shared S gene homology of 93.6%-95.2% in nucleotide identities and 92.4%-94.9% in amino acid identities. Compared with vaccine strain CV777, three additional N- glycosylation sites were formed and one N-glycosylation site was disrupted in the 16 isolated strains. In sum, currently, the main pathogens of piglet diarrhea were PEDV mutants. Prevention and control of porcine epidemic diarrhea should be paid attention to seasonal fluctuations and accelerate the development of epidemic strain vaccine. Key words: porcine epidemic diarrhea virus S gene molecular characteristic phylogenetic analysis antigenic analysis