Xu Lei, Tao Qian, Xu Tong, Yang Yanting, Zhang Yang, Liu Zheyan, Zhou Yuancheng, Zhu Ling, Xu Zhiwen
Key Laboratory of Animal Diseases and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.
Livestock and Poultry Biological Products Key Laboratory of Sichuan Province, Sichuan Animal Science Academy, Chengdu, China.
Front Vet Sci. 2024 Aug 7;11:1438354. doi: 10.3389/fvets.2024.1438354. eCollection 2024.
Pseudorabies virus is a major pathogen in the pig industry, causing substantial economic losses. The emergence of pseudorabies virus variant strains in China has led to extensive spread, raising concerns about their potential impact. However, the differences in pathogenicity between the classical strains and the variant strains of genotype II are not well understood. In this study, we isolated three pseudorabies virus strains to evaluate their replication characteristics and to examine the differences in virulence genes among various subgenotypes strains. Additionally, a piglet infection model was utilized to investigate the clinical features of infection, tissue tropism, and the inflammatory responses induced by these strains. Our results showed that the genotype II variant strains (MS, XJ, LS, and CZ) had significantly larger plaque sizes and higher replication capacities than the genotype II classical strain Fa. The animal experiments revealed significant differences in pathogenicity among the pseudorabies virus subgenotype strains, with the variant strains showing higher mortality rates, more severe clinical symptoms, increased nasal virus shedding, and a more robust inflammatory response compared to the genotype II classical strain. There were also notable differences in tissue tropism among the strains. In terms of tissue viral loads, the genotype II variant strains did not exhibit a significant advantage over the genotype I classical strain. Furthermore, our findings indicate that antibodies against the genotype II classical strains have a reduced neutralizing capacity against the genotype II variant strains. On the other hand, antibodies against the genotype II variant strains displayed similar neutralizing abilities against both classical and variant strains. Overall, these findings offer important insights into the distinctions among pseudorabies virus subgenotypes and their implications for the clinical control of pseudorabies virus infections in pig farming.
伪狂犬病病毒是养猪业中的主要病原体，会造成巨大经济损失。中国伪狂犬病病毒变异株的出现导致了广泛传播，引发了人们对其潜在影响的担忧。然而，II型经典毒株与变异毒株之间的致病性差异尚未得到充分了解。在本研究中，我们分离出三株伪狂犬病病毒毒株，以评估它们的复制特性，并研究不同亚基因型毒株之间毒力基因的差异。此外，利用仔猪感染模型来研究感染的临床特征、组织嗜性以及这些毒株诱导的炎症反应。我们的结果表明，II型变异毒株（MS、XJ、LS和CZ）的蚀斑大小明显大于II型经典毒株Fa，且复制能力更高。动物实验显示，伪狂犬病病毒亚基因型毒株之间在致病性上存在显著差异，与II型经典毒株相比，变异毒株的死亡率更高、临床症状更严重、鼻腔病毒排出量增加且炎症反应更强。各毒株在组织嗜性方面也存在显著差异。在组织病毒载量方面，II型变异毒株相对于I型经典毒株没有显著优势。此外，我们的研究结果表明，针对II型经典毒株的抗体对II型变异毒株的中和能力降低。另一方面，针对II型变异毒株的抗体对经典毒株和变异毒株均表现出相似的中和能力。总体而言，这些发现为伪狂犬病病毒亚基因型之间的差异及其对养猪业中伪狂犬病病毒感染临床防控的影响提供了重要见解。
