2018-2020年中国部分省市猪流行性腹泻病毒S1基因的监测及遗传变异分析

【目的】 调查中国规模化猪场猪流行性腹泻病毒(Porcine epidemic diarrhea virus，PEDV)的流行情况。【方法】 利用RT-PCR检测方法对2018-2020年采集于全国11个省市318个规模化猪场的2 391份样品进行PEDV核酸检测，对30份阳性样品进行S1全基因扩增与测序，并利用MegAlign、Mega 7.0等软件进行分析。【结果】 2018-2020年，猪场PEDV核酸阳性率分别为48.57%、10.96%和4.72%，样品PEDV核酸阳性率分别为28.97%、8.27%和7.50%，猪场和样品PEDV核酸阳性率呈现逐年下降的趋势。S1基因相似性分析显示，获得的30株毒株全部为GⅡ基因型，其中17株毒株为GⅡa基因亚型、5株毒株为GⅡb亚型、8株毒株为GⅡc亚型，GⅡa基因亚型毒株为2018-2020年流行的主要毒株类型；30株毒株S1基因序列之间核苷酸相似性为93.0%~99.5%, 氨基酸相似性为91.7%~100%，其中22株毒株与2017-2018年流行的GⅡ基因型毒株相比S1氨基酸序列表现出特征性插入和缺失。【结论】 本研究结果为监测和分析中国PEDV的变异和演化提供了临床数据，为猪流行性腹泻防控和疫苗研制提供了参考。

Surveillance and Genetic Variation Analysis of S1 Gene of Porcine Epidemic Diarrhea Virus in Part Provinces and Municipalities of China from 2018 to 2020

【Objective】 This study was aimed to survey the prevalence of Porcine epidemic diarrhea virus (PEDV) in large-scale pig farms in China.【Method】 2 391 samples collected from 318 large-scale pig farms in 11 provinces and municipalities of China from 2018 to 2020 were tested for PEDV nucleic acid using RT-PCR.The S1 gene of 30 positive samples were amplified and sequenced, and analyzed by MegAlign, Mega 7.0 and other softwares.【Result】 From 2018 to 2020, the PEDV nucleic acid positive rates in pig farms were 48.57%, 10.96%, and 4.72%, respectively, and the PEDV nucleic acid positive rates in samples were 28.97%, 8.27%, and 7.50%, respectively.The positive rate of PEDV nucleic acid in pig farms and samples showed a downward trend year by year.The similarity analysis of S1 gene showed that all the 30 strains obtained in this experiment were GⅡ genotype, of which 17 strains were GⅡa subtype, 5 strains were GⅡb subtype, and 8 strains were GⅡc subtype, GⅡa subtype strains were the main types of strains circulating from 2018 to 2020.The nucleotide similarity among the 30 strains sequence was 93.0%-99.5%, and the amino acid similarity was 91.7%-100%, compared with the GⅡ genotype strains prevalent from 2017 to 2018, the S1 amino acid sequences of 22 strains showed characteristic insertion and deletion.【Conclusion】 The results provided clinical data support for surveying and analyzing the variation and evolution of PEDV in China, and provided reference for porcine epidemic diarrhea prevention and control and vaccine development.