Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506, United States.
Virus Res. 2012 Mar;164(1-2):68-77. doi: 10.1016/j.virusres.2011.11.018. Epub 2011 Dec 17.
Porcine circovirus-associated disease (PCVAD) encompasses a group of complex, multi-factorial syndromes, which are dependent on infection with porcine circovirus type 2 (PCV2). Current strains of PCV2 circulating in the field are classified into two groups, termed PCV2a and PCV2b. Outbreaks of severe PCVAD in North America and other countries are often linked to a shift from PCV2a to PCV2b as the predominant genotype. Therefore, genotype-specific differences in pathogenesis and antigenicity have been suggested. Overall, evidence suggests that virulence is a function of the specific PCV2 isolate, regardless of genotype. In addition, only minor antigenic differences have been reported. In terms of immunopathogenesis, a conserved decoy epitope, located in the C-terminal region of the capsid protein, provides an explanation for the inability to identify pathogenic differences between genotypes. Finally, genetic variation in PCV2 and the resulting consequences with respect to vaccination and diagnostics are discussed.
猪圆环病毒相关疾病（PCVAD）包括一组复杂的、多因素的综合征，这些综合征依赖于猪圆环病毒 2 型（PCV2）的感染。目前在田间循环的 PCV2 菌株分为两个组，称为 PCV2a 和 PCV2b。北美的严重 PCVAD 暴发和其他国家的暴发通常与从 PCV2a 到 PCV2b 的主要基因型转变有关。因此，已提出在发病机制和抗原性方面存在基因型特异性差异。总的来说，有证据表明，毒力是特定 PCV2 分离株的功能，而与基因型无关。此外，仅报道了轻微的抗原差异。在免疫发病机制方面，位于衣壳蛋白 C 末端区域的保守诱饵表位为无法确定基因型之间的致病性差异提供了一个解释。最后，讨论了 PCV2 的遗传变异以及对疫苗接种和诊断的影响。
