Mei Yongjie, Chen Jianguo, Chen Yingyu, Hu Changmin, Chen Xi, Guo Aizhen
National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
The Cooperative Innovation Centre for Sustainable Pig Production, Hubei International Scientific and Technological Cooperation Base of Veterinary Epidemiology, Wuhan 430070, China.
Microorganisms. 2025 Mar 31;13(4):796. doi: 10.3390/microorganisms13040796.
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is one of the most significant infectious agents threatening the global pig industry. Due to its high mutation and recombination rates, the prevalence of PRRSV in domestic pig populations is complex. To better understand the epidemiology of PRRSV, we conducted a large-scale investigation in eastern China, focusing on pig farms with a history of high abortion rates. A total of 14,934 pig samples were collected from 11 sow farms and 53 fattening farms across three provinces. Among these, 13.0% of the collected samples tested positive for PRRSV, with specific prevalence rates of 19.7% in sows and 12.4% in piglets. Genetic evolution analysis of the GP5 gene from 43 PRRSV strains identified in this study revealed that NADC30-like, NADC34-like, and HP-PRRSV were the predominant lineages in domestic pig farms. The NADC30-like genotype was the most dominant and had evolved into three subgenotypes, while the NADC34-like strains had diverged into two subgenotypes. Further analysis of the Nsp2 gene from 18 strains indicated that the NSP2 gene of multiple NADC34-like strains was closely related to that of the NADC30-like, suggesting that the NADC34-like strains are primarily recombinant viruses. Sequence comparison of the Nsp2 gene showed that both NADC30-like and NADC34-like viruses share 111 amino acid deletions at positions 322-433 and 21 amino acid deletions at positions 539-558 in the Nsp2 gene coding region. For the first time, the pathogenicity of a representative NADC34-like virus isolated in China was evaluated in pregnant sow. The results showed that infected sows exhibited an increased body temperature, ear cyanosis, and typical edema and cyanosis of the external genitalia. Moreover, all infected sows experienced miscarriage, with 100% of the aborted piglets being stillbirths exhibiting a high virus load. These findings indicate that this NADC34-like virus is highly virulent to sows.
猪繁殖与呼吸综合征病毒（PRRSV）是威胁全球养猪业的最重要的传染性病原体之一。由于其高突变率和重组率，PRRSV在国内猪群中的流行情况较为复杂。为了更好地了解PRRSV的流行病学，我们在中国东部进行了大规模调查，重点关注有高流产率历史的猪场。从三个省份的11个母猪场和53个育肥猪场共采集了14934份猪样本。其中，13.0%的采集样本PRRSV检测呈阳性，母猪的特定流行率为19.7%，仔猪为12.4%。对本研究中鉴定出的43株PRRSV毒株的GP5基因进行遗传进化分析表明，NADC30样、NADC34样和高致病性PRRSV（HP-PRRSV）是国内猪场的主要谱系。NADC30样基因型最为 dominant，已进化为三个亚基因型，而NADC34样毒株已分化为两个亚基因型。对18株毒株的Nsp2基因进行进一步分析表明，多个NADC34样毒株的NSP2基因与NADC30样毒株的NSP2基因密切相关，这表明NADC34样毒株主要是重组病毒。Nsp2基因的序列比较表明，NADC30样和NADC34样病毒在Nsp2基因编码区的322-433位均有111个氨基酸缺失，在539-558位均有21个氨基酸缺失。首次对在中国分离的一株代表性NADC34样病毒在怀孕母猪中的致病性进行了评估。结果表明，感染母猪体温升高、耳部发绀，外阴出现典型的水肿和发绀。此外，所有感染母猪均发生流产，100%的流产仔猪为死胎，病毒载量高。这些发现表明，这种NADC34样病毒对母猪具有高致病性。
