Yu Jiarong, Chen Pengfei, Liu Ruilin, Lao Mengqin, Zhu Junrui, Zhou Shuting, Jiang Jijie, Huang Shijing, Tong Wu, Jiang Yifeng, Gao Fei, Yu Lingxue, Yu Hai, Liu Changlong, Yang Zhibiao, Tong Guangzhi, Zhou Yanjun
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Science, Shanghai, China.
Transbound Emerg Dis. 2023 May 9;2023:5544724. doi: 10.1155/2023/5544724. eCollection 2023.
Diarrhea outbreaks in piglets on pig farms are commonly attributed to porcine epidemic diarrhea virus (PEDV) infection. This research analyzed the S gene prevalence variation and recombination patterns in PEDV GII strains. Throughout the previous two years, 172 clinical samples of piglet diarrhea have been collected, from which 24 PEDV isolates have been isolated. Analysis of the evolutionary relationships among all 24 S genes revealed that 21 were most closely related to strains within the GII-a subgroup. The 2 isolates grouped into one clade with the GII-b subgroup. According to the mutation analysis of the amino acids (aa) that encode the S protein, 43 of the common aa in strains of the GII subtype were found to have undergone a change in polarity or charge, and 36 of these aa had a mutation frequency of more than 90%. Three different aa mutation sites were identified as exclusive to GII-a subtype strains. The genomes of three PEDV isolates were sequenced, and the resulting range in genome length was 28,035-28,041 nt. The results of recombination analysis showed that the SD1 isolate is a novel strain recombinant from the foreign S-INDEL strain and a domestic GII subtype strain. Based on the findings, the PEDV GII-a strain has been the most circulating strain in several parts of China during the previous two years. Our study reveals for the first time the unique change of aa mutations in the S protein of the GII-a subtype strain and the new characteristics of the recombination of foreign strains and domestic GII subtype strains, indicating that it is crucial to monitor the epidemic dynamics of PEDV promptly to prevent and control the occurrence of PED effectively.
猪场仔猪腹泻疫情通常归因于猪流行性腹泻病毒（PEDV）感染。本研究分析了PEDV GII毒株的S基因流行变异和重组模式。在过去两年中，共收集了172份仔猪腹泻临床样本，从中分离出24株PEDV毒株。对所有24个S基因的进化关系分析表明，其中21个与GII-a亚组内的毒株关系最为密切。另外2个毒株与GII-b亚组归为一个进化枝。通过对编码S蛋白的氨基酸（aa）突变分析发现，GII亚型毒株中43个常见氨基酸的极性或电荷发生了变化，其中36个氨基酸的突变频率超过90%。鉴定出3个不同的氨基酸突变位点为GII-a亚型毒株所特有。对3株PEDV毒株的基因组进行测序，基因组长度范围为28,035-28,041 nt。重组分析结果表明，SD1毒株是一株由国外S-INDEL毒株和国内GII亚型毒株重组而成的新型毒株。基于这些发现，PEDV GII-a毒株在过去两年中一直是中国部分地区最主要的流行毒株。我们的研究首次揭示了GII-a亚型毒株S蛋白氨基酸突变的独特变化以及国外毒株与国内GII亚型毒株重组的新特征，表明及时监测PEDV的流行动态对于有效预防和控制PED的发生至关重要。
