Chen Dengjin, Huang Yi, Guo Yating, Wang Lihong, Zhang Yongning, Zhou Lei, Ge Xinna, Han Jun, Guo Xin, Yang Hanchun
Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Animals (Basel). 2022 Jun 20;12(12):1588. doi: 10.3390/ani12121588.
Porcine circovirus 3 (PCV3) is an emerging virus, causing substantial economic losses in pig populations, that was first detected in 2016. Furthermore, the virus has already been reported in Europe, the Americas, and Asia, including China, indicating that the virus has spread worldwide. However, the molecular epidemiology of PCV3 still needs further study. To investigate PCV3 epidemiological characteristics in China, 2707 serum samples of pigs were randomly collected from 17 provinces in China between September 2018 and March 2022 and analyzed via PCR assays. The study showed that PCV3 infection was prevalent in the overall population with 31.07% (841/2707) and 100.0% (17/17) at sample and province levels, respectively, though the positivity rate of PCV3 varied from 7.41 to 70.0% in different provinces, suggesting that PCV3 infection has a widespread distribution in China. We selected 22 serum samples from different regions that had high levels of viral DNA for amplification and sequenced their ORF2 (Cap) gene. According to the phylogenetic analysis, all isolates in the current study could be grouped into two separate subclades, with 15 strains belonging to clade 3a and 7 strains belonging to clade 3b, indicating that PCV3a and PCV3b were the predominant subtypes in the regions of China studied. Meanwhile, additional analysis revealed that the capsid gene sequences identified in this study displayed 97.4699.8% nucleotide (nt) and 97.06100% amino acid (aa) sequence similarity with other PCV3 available reference strains, respectively. In general, our studies provide important insights for understanding the prevalence and evolution of PCV3 in China and will guide future efforts to develop measures for preventing and controlling the disease.
猪圆环病毒3型（PCV3）是一种新出现的病毒，自2016年首次被发现以来，给猪群造成了巨大的经济损失。此外，该病毒已在欧洲、美洲和亚洲（包括中国）被报道，这表明该病毒已在全球范围内传播。然而，PCV3的分子流行病学仍需进一步研究。为了调查中国PCV3的流行病学特征，于2018年9月至2022年3月期间从中国17个省份随机采集了2707份猪血清样本，并通过PCR检测进行分析。研究表明，PCV3感染在总体猪群中普遍存在，样本水平和省份水平的感染率分别为31.07%（841/2707）和100.0%（17/17），尽管不同省份的PCV3阳性率在7.41%至70.0%之间有所不同，这表明PCV3感染在中国分布广泛。我们从不同地区选择了22份病毒DNA水平较高的血清样本进行扩增，并对其ORF2（Cap）基因进行测序。根据系统发育分析，本研究中的所有分离株可分为两个独立的亚分支，其中15株属于3a分支，7株属于3b分支，这表明PCV3a和PCV3b是所研究的中国地区的主要亚型。同时，进一步分析显示，本研究中鉴定的衣壳基因序列与其他可用的PCV3参考菌株的核苷酸（nt）序列相似性为97.46%至99.8%，氨基酸（aa）序列相似性为97.06%至100%。总体而言，我们的研究为了解PCV3在中国的流行情况和进化提供了重要见解，并将指导未来制定疾病预防和控制措施的工作。
