Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
J Comp Pathol. 2022 Nov;199:88-98. doi: 10.1016/j.jcpa.2022.09.012. Epub 2022 Nov 5.
The objective of this study was to compare the virulence of four porcine circovirus type 2 (PCV2) genotypes (2a, 2b, 2d and 2e). Pigs were infected with one of these four genotypes. Pigs were also dually infected with Mycoplasma hyopneumoniae and one of the four PCV2 genotypes. Virulence was determined based on the amount of PCV2 loads in the blood and lymph nodes and the severity of lymphoid lesions. Marked differences in virulence were found among the four genotypes. Within the single infection model, PCV2a, PCV2b and PCV2d were more virulent than PCV2e, while significant differences in virulence were not found among the PCV2a, PCV2b and PCV2d groups. Within the dual infection model, PCV2d was more virulent than the other three PCV2 genotypes. Mycoplasma hyopneumoniae potentiated the severity of PCV2-associated lymphoid lesions and increased the amount of PCV2 loads in the blood and lymph nodes, regardless of the PCV2 genotype. By contrast, PCV2 was not able to potentiate the severity of mycoplasmal-induced lung lesions or the level of M. hyopneumoniae laryngeal load. The results of this study demonstrate that PCV2d is of major clinical importance, while PCV2e is of minor clinical importance.
本研究旨在比较四种猪圆环病毒 2 型（PCV2）基因型（2a、2b、2d 和 2e）的毒力。猪只感染这四种基因型之一。猪只还同时感染肺炎支原体和四种 PCV2 基因型之一。毒力是根据血液和淋巴结中 PCV2 载量以及淋巴病变的严重程度来确定的。四种基因型之间存在明显的毒力差异。在单一感染模型中，PCV2a、PCV2b 和 PCV2d 比 PCV2e 更具毒力，而 PCV2a、PCV2b 和 PCV2d 组之间的毒力差异不显著。在双重感染模型中，PCV2d 比其他三种 PCV2 基因型更具毒力。肺炎支原体增强了 PCV2 相关淋巴病变的严重程度，并增加了血液和淋巴结中 PCV2 载量，而与 PCV2 基因型无关。相比之下，PCV2 不能增强支原体引起的肺病变的严重程度或 M. hyopneumoniae 喉载量水平。本研究结果表明，PCV2d 具有重要的临床意义，而 PCV2e 则具有较小的临床意义。
