Du Yingbin, Chen Jingyi, Ren Tianze, Xie Chunying, Zhang Yiye, Fang Liurong, Zhou Yanrong
National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
Key Laboratory of Preventive Veterinary Medicine in Hubei Province, the Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.
Vet Sci. 2025 May 29;12(6):530. doi: 10.3390/vetsci12060530.
Due to its high genomic variability, the epidemiological landscape of porcine reproductive and respiratory syndrome virus (PRRSV) has become increasingly complex in recent years. From 2022 to 2023, we collected a total of 1044 clinical samples from pigs suspected of PRRSV infection in China and discovered a PRRSV-positive rate of 29.8% (311/1044) using RT-PCR targeting the nsp2 gene. Among these positive samples, NADC30/34-like PRRSV, highly pathogenic PRRSV (HP-PRRSV), and classical PRRSV strains accounted for 60.1%, 37.9%, and 4.5%, respectively. These results indicate that the most prevalent PRRSV strains in China are NADC30/34-like PRRSV, followed by HP-PRRSV. Two PRRSV strains, JX03 and HN08, were isolated, and TCID assays were performed to determine their titers at different time points post-infection, revealing differences in their proliferation kinetics. Phylogenetic, amino acid sequence, and recombination analyses demonstrated that the JX03 and HN08 strains cluster within lineage 8 (HP-PRRSV) and sublineage 1.5 (NADC34-like PRRSV), respectively. Notably, the HN08 strain was identified as a recombinant between the NADC30-like and NADC34-like strains, while no recombination event was detected in the JX03 strain. Pathogenicity assessments showed that the JX03 strain exhibited higher pathogenicity than the CHN-HB-2018 strain (a NADC30-like PRRSV strain was previously isolated by our lab), as evidenced by differences in clinical signs and mortality rates in piglets. In contrast, HN08 displayed no obvious clinical symptoms or mortality, revealing lower pathogenicity than the CHN-HB-2018 strain. These findings provide valuable information on the epidemiological and genetic characteristics of PRRSV strains in China, laying a foundation for the development of effective strategies against PRRSV.
由于其高度的基因组变异性，近年来猪繁殖与呼吸综合征病毒（PRRSV）的流行病学态势变得日益复杂。2022年至2023年期间，我们在中国共收集了1044份疑似感染PRRSV的猪的临床样本，通过针对nsp2基因的逆转录聚合酶链反应（RT-PCR）检测发现PRRSV阳性率为29.8%（311/1044）。在这些阳性样本中，NADC30/34样PRRSV、高致病性PRRSV（HP-PRRSV）和经典PRRSV毒株分别占60.1%、37.9%和4.5%。这些结果表明，中国最流行的PRRSV毒株是NADC30/34样PRRSV，其次是HP-PRRSV。分离出了两株PRRSV毒株JX03和HN08，并进行了半数组织培养感染剂量（TCID）测定以确定它们在感染后不同时间点的滴度，揭示了它们增殖动力学的差异。系统发育、氨基酸序列和重组分析表明，JX03和HN08毒株分别聚类于第8分支（HP-PRRSV）和1.5亚分支（NADC34样PRRSV）。值得注意的是，HN08毒株被鉴定为NADC30样和NADC34样毒株之间的重组体，而JX03毒株未检测到重组事件。致病性评估表明，JX03毒株表现出比CHN-HB-2018毒株（我们实验室先前分离的一株NADC30样PRRSV毒株）更高的致病性，仔猪的临床症状和死亡率差异证明了这一点。相比之下，HN08未表现出明显的临床症状或死亡率，显示出比CHN-HB-2018毒株更低的致病性。这些发现为中国PRRSV毒株的流行病学和遗传特征提供了有价值的信息，为制定有效的抗PRRSV策略奠定了基础。
