State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
Viruses. 2023 Jun 30;15(7):1492. doi: 10.3390/v15071492.
Porcine epidemic diarrhea virus (PEDV), a re-emerging enteropathogenic coronavirus, has become the predominant causative agent of lethal diarrhea in piglets, resulting in huge economic losses in many countries. Furthermore, the rapid variability of this virus has increased the emergence of novel variants with different pathogenicities. In this study, 633 fecal samples collected from diarrheic piglets in China during 2017-2019 were analyzed, and 50.08% (317/633) of these samples were PEDV-positive. The full-length spike (S) genes of 36 samples were sequenced, and a genetic evolution analysis was performed. The results showed that thirty S genes belonged to the GII-a genotype and six S genes belonged to the GII-b genotype. From the PEDV-positive samples, one strain, designated ECQ1, was successfully isolated, and its full-length genome sequence was determined. Interestingly, ECQ1 is a recombinant PEDV between the GII-a (major parent) and GII-b (minor parent) strains, with recombination occurring in the S2 domain of the S gene. The pathogenicity of ECQ1 was assessed in 5-day-old piglets and compared with that of the strain EHuB2, a representative of GII-a PEDV. Although both PEDV strains induced similar fecal viral shedding in the infected piglets, ECQ1 exhibited lower pathogenicity than did EHuB2, as evidenced by reduced mortality and less severe pathological changes in the intestines. These data suggest that PEDV strain ECQ1 is a potential live virus vaccine candidate against porcine epidemic diarrhea.
猪流行性腹泻病毒（PEDV）是一种重新出现的肠致病性冠状病毒，已成为仔猪致死性腹泻的主要病原体，给许多国家造成了巨大的经济损失。此外，该病毒的快速变异增加了具有不同致病性的新型变异株的出现。在本研究中，分析了 2017 年至 2019 年期间从中国腹泻仔猪中采集的 633 份粪便样本，其中 50.08%（317/633）的样本为 PEDV 阳性。对 36 个样本的全长刺突（S）基因进行了测序，并进行了遗传进化分析。结果表明，30 个 S 基因属于 GII-a 基因型，6 个 S 基因属于 GII-b 基因型。从 PEDV 阳性样本中成功分离出一株病毒，命名为 ECQ1，并测定了其全长基因组序列。有趣的是，ECQ1 是一株 GII-a（主要亲本）和 GII-b（次要亲本）之间的 PEDV 重组病毒，其 S 基因的 S2 结构域发生了重组。在 5 日龄仔猪中评估了 ECQ1 的致病性，并与 GII-a PEDV 的代表株 EHuB2 进行了比较。尽管两种 PEDV 株均在感染仔猪中引起类似的粪便病毒脱落，但 ECQ1 的致病性低于 EHuB2，表现在死亡率降低和肠道病变减轻。这些数据表明，PEDV 株 ECQ1 是一种针对猪流行性腹泻的潜在活病毒疫苗候选株。
