Institute of Military Veterinary Medicine, Academy of Military Medical Sciences, Changchun, 130122, China; College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, China.
Institute of Military Veterinary Medicine, Academy of Military Medical Sciences, Changchun, 130122, China; College of Veterinary Medicine, Jilin University, Changchun, 130012, China.
Vet Microbiol. 2020 Aug;247:108756. doi: 10.1016/j.vetmic.2020.108756. Epub 2020 Jun 13.
Porcine circovirus type 3 (PCV3) infection causes substantial economic losses in pig populations since its discovery in 2016. However, PCV3 molecular epidemiology remains need further study. In order to assess the prevalence of PCV3 infection in China, 4094 clinical samples from 271 pig farms in 10 provinces of China were evaluated by PCR. It was shown that the overall prevalence of PCV3 infection was 29.3 % (1200/4094) and 74.2 % (201/271) at sample and farm levels respectively, suggesting that PCV3 infection is prevalent in China. Furthermore, a statistical analysis showed PCV3 might exacerbate PCV2 and PRRSV infection rate and have a potential association with pig clinical disease. In addition, we sequenced the entire genome of 57 PCV3 strains; homology analysis showed that PCV3 strains have more than 96 % similarities at the nucleotide level, and PCV3 shares less than 60 % similarities with other circoviruses. By comparing the total 673 PCV3 strains from the NCBI GenBank, we found the major of amino acid mutations are located in predicted epitope regions and the mutations ratio changed during PCV3 evolution. Phylogenetic analysis revealed that all isolates belonged to PCV3a and PCV3b, and increasing PCV3a and decreasing PCV3b trends were observed during PCV3 evolution. Overall, this study provides important insights for understanding PCV3 prevalence, pathogenesis, and evolution and will guide future efforts to develop effective preventive and control measures.
猪圆环病毒 3 型（PCV3）自 2016 年发现以来，给猪群造成了巨大的经济损失。然而，PCV3 的分子流行病学仍需进一步研究。为了评估 PCV3 在中国的感染流行情况，本研究通过 PCR 对来自中国 10 个省 271 个猪场的 4094 份临床样本进行了评估。结果显示，PCV3 总感染率为 29.3%（4094/1200）和 74.2%（271/201），提示 PCV3 在中国流行。此外，统计分析显示 PCV3 可能加重 PCV2 和 PRRSV 的感染率，并与猪临床疾病有潜在关联。此外，我们对 57 株 PCV3 进行了全基因组测序；同源性分析显示，PCV3 株在核苷酸水平上的相似度超过 96%，与其他圆环病毒的相似度不到 60%。通过比较 NCBI GenBank 中 673 株 PCV3 株的全基因组序列，我们发现大多数氨基酸突变位于预测的表位区域，并且在 PCV3 进化过程中突变比例发生了变化。系统进化分析表明所有分离株均属于 PCV3a 和 PCV3b，并且在 PCV3 进化过程中观察到 PCV3a 的增加和 PCV3b 的减少趋势。总之，本研究为了解 PCV3 的流行、发病机制和进化提供了重要的见解，并将指导未来制定有效的预防和控制措施。
