Zhengzhou Major Pig Disease Prevention and Control Laboratory, College of Veterinary Medicine, Henan Agricultural University, Zhengdong New District Longzi Lake 15#, Zhengzhou 450046, China.
Henan Houyi Biological Engineering Co., Ltd., Zhengzhou Airport Economic Comprehensive Experimental Zone Jingang Avenue, Zhengzhou 451161, China.
Viruses. 2022 Feb 27;14(3):487. doi: 10.3390/v14030487.
Porcine epidemic diarrhea virus (PEDV) is the major pathogen that causes diarrhea and high mortality in newborn piglets, with devastating impact on the pig industry. To further understand the molecular epidemiology and genetic diversity of PEDV field strains, in this study the complete genomes of four PEDV variants (HN2021, CH-HNYY-2018, CH-SXWS-2018, and CH-HNKF-2016) obtained from immunized pig farms in central China between 2016 to 2021 were characterized and analyzed. Phylogenetic analysis of the genome and S gene showed that the four strains identified in the present study had evolved into the subgroup G2a, but were distant from the vaccine strain CV777. Additionally, it was noteworthy that a new PEDV strain (named HN2021) belonging to the G2a PEDV subgroup was successfully isolated in vitro and it was further confirmed by RT-PCR that this isolate had a large natural deletion at 207-373 nt of the ORF3 gene, which has never been reported before. Particularly, in terms of pathogenicity evaluation, colostrum deprivation piglets challenged with PEDV HN2021 showed severe diarrhea and high mortality, confirming that PEDV HN2021 was a virulent strain. Hence, PEDV strain HN2021 of subgroup G2a presents a promising vaccine candidate for the control of recurring porcine epidemic diarrhea (PED) in China. This study lays the foundation for better understanding of the genetic evolution and molecular pathogenesis of PEDV.
猪流行性腹泻病毒（PEDV）是导致新生仔猪腹泻和高死亡率的主要病原体，对养猪业造成了毁灭性的影响。为了进一步了解 PEDV 田间毒株的分子流行病学和遗传多样性，本研究对 2016 年至 2021 年期间中国中部免疫猪场获得的 4 种 PEDV 变异株（HN2021、CH-HNYY-2018、CH-SXWS-2018 和 CH-HNKF-2016）的完整基因组进行了特征分析和鉴定。基因组和 S 基因的系统进化分析表明，本研究中鉴定的 4 株分离株已进化为 G2a 亚群，但与疫苗株 CV777 相距较远。此外，值得注意的是，本研究成功地从体外分离到一种新的 G2a 亚群 PEDV 株（命名为 HN2021），并通过 RT-PCR 进一步证实该分离株在 ORF3 基因的 207-373nt 处存在一个大的天然缺失，这是以前从未报道过的。特别是在致病性评估方面，用 PEDV HN2021 攻毒的初乳剥夺仔猪表现出严重的腹泻和高死亡率，证实 PEDV HN2021 是一种毒力株。因此，G2a 亚群的 PEDV 株 HN2021 为控制中国反复发生的猪流行性腹泻（PED）提供了一种有前途的疫苗候选株。本研究为更好地了解 PEDV 的遗传进化和分子发病机制奠定了基础。
