Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus-associated diseases in swine, the most common of which are postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS). To investigate the prevalence and genetic diversity of PCV2 in Hebei Province, Northern China, from 2016 to 2019, a total of 448 suspected cases of PCV2 infection were studied, and 179 samples were positive for PCV2. A pathological and histopathological examination suggested PCV2 to be cause of the observed lesions. Phylogenetic analysis showed that four genotypes were prevalent in Hebei Province: PCV2a, 2b, 2d, and 2e. Analysis of PCV2 strains using RDP4 and SimPlot showed that there were genetic recombination events among PCV2 strains in Hebei Province. A total of 3284 serum samples were screened by ELISA, and the positive rate of PCV2 antibodies was 73.9% (2428/3284). This study provides a scientific reference for the prevention and treatment of PCV2 in Hebei Province.

为了解猪圆环病毒型(porcine circovirus3,PCV3)在河北省的流行情况及遗传变异特点,本研究在2017年2月至2018年7月间,从河北省不同地区60个猪场采集了310份不同临床症状表现的发病猪组织样本,应用PCR方法对其进行检测.结果 显示该地区PCV3阳性率为16.5％(51/310),猪场阳性率为45.0％(27/60),对不同临床症状发病率分析显示PCV3在表现为繁殖障碍及腹泻猪群中具有较高的阳性率,且易与PCV2发生共同感染.对获得的8株PCV3的cap基因进行测序及同源性分析显示,所得8条序列之间的核苷酸相似性为98.0％～99.7％,与24条国内外参考株之间的核苷酸相似性为98.0％～100.0％.对cap基因所推导的氨基酸序列进行分析发现cap基因的主要突变位点发生在24,27,77及150位,其中24和27位主要发生了A24V和R27K变异.对32条序列进行进化树的构建发现,进化树可分为3a、3b和3c 3个基因群,河北分离株主要分布于3a基因群和3c基因群,表明了河北省PCV3流行株相对稳定.我们的研究结果为PCV3在河北省的流行及进化特点提供了理论参考,这些数据可为该地区PCV3的诊断及综合防控提供科学依据.

This study was conducted to understand porcine deltacoronavirus (PDCoV) epidemic situation, and provide a tool for PDCoV serum antibody detection and the epidemiological investigation. Prokaryotic expression of recombinant PDCoV partial spike (S) protein was used as detection antigen, and an indirect ELISA antibody detection method based on PDCoV S1 protein was established. The method was used to detect 570 serum samples collected from some pig farms in Hebei from January to December 2017. The results showed that the established ELISA method of PDCoV IgG antibody in this study could specifically detect PDCoV antibody; no cross-reaction with antisera against porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever (CSF) and pseudorabies virus (PRV) was found. The coefficients of variation (CV) of repeated in-batch test was 1.9%-5.4%, CV of batch-to-batch test was 2.3%-5.1%. In 570 blood samples, 105 were positive, and the positive rate was 18.4% (105/570), which was higher than the positive rate of PDCoV IgG antibody (11%) in Hebei from January 2016 to October 2016. It is suggested that the infection rate of PDCoV in Hebei is on the rise. The ELISA method established in this study had the advantages of high sensitivity, strong specificity and good reproducibility, and can be used for the detection of clinical PDCoV serum antibodies.Copyright © 2019, Chinese Journal of Animal Science and Veterinary Medicine Co., Ltd. All right reserved.

为建立同时快速定量检测猪博卡病毒(PBoV)G1基因群和猪流行性腹泻病毒(PEDV)的方法,本研究参照GenBank登录的PBoV的NP1基因和PEDV的M基因保守序列,设计了引物和探针,经优化反应条件后,建立了能够同时检测PBoV G1基因群和PEDV的双重TaqMan荧光定量PCR方法.特异性试验结果显示该方法与PCV2、PRV、PDCoV、PRoV和TGEV无交叉反应,敏感性试验结果显示该方法对PBoV、PEDV的质粒标准品检测下限分别为21.8拷贝/μL和31.7拷贝/μL;且组内、组间变异系数均小于4％,重复性好.应用本实验建立的方法对2017年5月～2018年8月,河北省部分地区采集的142份仔猪腹泻样品检测结果显示,PBoV G1阳性率为18.3％(26/142),PEDV阳性率为62.7％(89/142),其中PBoV G1与PEDV共感染率为10.6％(15/142),该方法优于常规PCR方法.本研究建立的双重TaqMan荧光定量PCR方法对PBoV和PEDV的准确检测、 病原监测、 流行病学调查等均具有重要意义.

Porcine bocavirus (PBoV), which belongs the genus Bocaparvovirus, has been identified throughout the world. However, serological methods for detecting anti-PBoV antibodies are presently limited. In the present study, an indirect enzyme-linked immunosorbent assay (PBoV-rNP1 ELISA) based on a recombinant form of nucleoprotein 1 (NP1) of PBoV was established for investigating the seroprevalence of PBoV in 2025 serum specimens collected in north-central China from 2016 to 2018, and 42.3% of the samples tested positive for anti-PBoV IgG antibodies, indicating that the seroprevalence of PBoV is high in pig populations in China.

Porcine deltacoronavirus (PDCoV) and porcine epidemic diarrhea virus (PEDV) are enterpathogenic coronavirus which cause acute diarrhea,vomiting,dehydration and mortality in neonatal piglets.In order to establish a real-time reverse transcription quantitative PCR (RT-qPCR) assay to detect PDCoV and PEDV,two pairs of specific primers were designed according to the conservative sequence of N gene (PDCoV) and M gene (PEDV) registered in GenBank.The genes of the conservative region were amplified and cloned into pMD19-T vector.Taking Mix 10 times the gradient dilution of recombinant plasmid as a standard template,a RT-qPCR to PDCoV and PEDV was established.The sensitivity,specificity and repeatability were tested.Results showed that the sensitivity of this RT-qPCR assay was 51 and 32 copies · μL 1 for PDCoV and PEDV,respectively.No cross-reaction was detected to PBoV,TGEV,PRV and PCV2.The RT-qPCR assay was applied to the detection of 130 clinical samples collected from Hebei province during 2016-2017.PDCoV positive rate was 16.9％,PEDV positive rate was 66.2％,and co-infection was 2.3 ％.The sensitivity of fluorescence quantitative PCR was significantly higher than that of ordinary RT-PCR.These results indicated that the detection assay could be applied for rapid and high through-put diagnosis of PDCoV and PEDV.

猪流行性腹泻(porcine epidemic diarrhea,PED)是由PEDV引起 仔猪腹泻,呕吐的一种高致死性的肠道 染病.本病在英国首先爆发,后逐渐扩展到欧洲,亚洲乃至全球,在2010年,我国多省份大面积发病,对我国的养猪业造成了严重的经济损失. PEDV属于冠状病毒科冠状病毒属,与猪传染性胃肠炎病毒(transmissible gastroenteritis virus,TGEV),猪丁型冠状病毒(Porcine deltacoronavirus,PDCoV)同科同属,且发病症状和病理变化极为相似,极难通过常规手段进行区分,因此,建立一种快速且准确的诊断PEDV的方式对PED的防治具有极其重要的意义.