猪流行性腹泻病毒、猪传染性胃肠炎病毒、猪A型轮状病毒多重RT-PCR方法的建立及其应用

为了建立一种能够同时检测猪流行性腹泻病毒(PEDV)、猪传染性胃肠炎病毒(TGEV)和猪A群轮状病毒(RVA)的敏感、特异的多重RT-PCR(mRT-PCR)方法,本试验分别针对PEDV和TGEV的N基因、RVA的VP7基因设计了4对引物(其中针对PEDV N基因的引物为内、外2对),结合mRT-PCR和PEDV的套式RT-PCR(nRTPCR),建立了检测PEDV、TGEV和RVA的mRT-PCR方法。mRT-PCR能够同时扩增出针对3种病毒的预期大小的目的核苷酸片段,与猪繁殖与呼吸综合征病毒、猪瘟病毒、伪狂犬病毒及猪圆环病毒2型等病毒无交叉反应;可以检测到PEDV、TGEV和RVA的最低核酸浓度分别为16.07、803.9和321.5μg/L。应用mRT-PCR检测了31份腹泻仔猪的血清、肛拭子或小肠组织,其中PEDV、TGEV与RVA的阳性率分别为61.29%、6.45%和25.81%,并检测到了PEDV与RVA或TGEV双重感染及PEDV、TGEV和RVA三重感染的样品。在检测临床样品时,mRT-PCR和单项RT-PCR检出PEDV、TGEV和RVA的符合率分别为96.77%、93.54%和93.54%。上述结果表明,mRTPCR能够快速鉴别检测PEDV、TGEV和RVA 3种病毒,PEDV是引起当前仔猪腹泻的主要病原。     

猪流行性腹泻病毒、传染性胃肠炎病毒、A群轮状病毒和嵴病毒多重RTPCR检测方法的建立及临床应用

本研究建立了可同时检测猪流行性腹泻病毒（Porcineepidemicdiarrheavirus,PEDV）、传染性胃肠炎病毒（TransmissiblegastroenteritisVirus,TGEV）、A群轮状病毒（GroupArotavirus,GARV）和猪嵴病毒（Porcinekobu—virus）的多重RT—PCR方法。检测中,建立的多重RT—PCR方法能够检测到500Pg的TGEV、PEDV、GARV和猪嵴病毒等量混合RNA模板,与常规的单一RT—PCR检测结果基本相同（检测TGEV、PEDV、GARV和猪嵴病毒的灵敏性分别为1000A、1000／6、93．33％和96．67％,特异性均为i00％）。结果表明,建立的多重RTPCR方法敏感性和特异性良好,可作为临床上猪病毒性腹泻病因快速、高效的诊断工具。应用该方法对2010—2012年华中地区190份腹泻仔猪样本进行检测,PEDV、TGEV、GARV和猪嵴病毒的阳性率分别为62．11％、0．53％、7．37％和82．11％。混合感染方面,PEDV和猪嵴病毒混合感染率为47．89％,PEDV和GARV混合感染率为4．74％,GARV和猪嵴病毒混合感染率为7．37％,PEDV、GARV和猪嵴病毒混合感染率为4．74％,未发现TGEV与其它3种病毒的混合感染情况。另外,有27份样本中仅检出PEDV（14．21％）,57份样本只检出猪嵴病毒（30％）。分析表明,我国自2010年底大面积暴发的病毒性腹泻是多病原混合感染造成的,主要病原为PEDV,猪嵴病毒在其中所起作用尚待进一步验证和研究。     

猪Delta冠状病毒、猪传染性胃肠炎病毒和猪流行性腹泻病毒多重RT-PCR检测方法的建立及应用

猪Delta冠状病毒(PDCoV)、猪流行性腹泻病毒(PEDV)和猪传染性胃肠炎病毒(TGEV)均是能引起仔猪腹泻的冠状病毒,通过临床症状和剖检很难鉴别诊断,建立同时检测且能够鉴别诊断这3种疾病的快速检测方法对于临床诊断具有重要的意义。参照GenBank中登录的PDCoV,NPEDV M和TGEV N基因的基因序列,利用Primer5.0设计合成3对能扩增特异性目的片段的引物,构建重组质粒,并对RT-PCR反应条件进行优化,建立了检测PDCoV,PEDV和TGEV的多重RT-PCR诊断方法,并对所建立的方法进行敏感性、特异性和重复性分析。利用该方法对河南176份临床样品进行检测,并与普通RT-PCR检测方法对该检测方法进行比较分析。结果表明,所建立的三重RT-PCR方法对PDCoV的最低检测量是3.14×103拷贝/μL;PEDV的最低检测量是3.88×104拷贝/μL和TGEV的最低检测量是3.68×104拷贝/μL。所建立的方法具有较好的特异性,对猪博卡病毒(PboV)、猪伪狂犬病病毒(PRV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪瘟(CSFV)和猪圆环病毒(PCV)等猪常见病毒的扩增结果均为阴性。应用所建立的三重RT-PCR方法对176份临床收集的仔猪腹泻样品进行PEDV,PDCoV和TGEV检测,并将检测结果和单重RT-PCR检测方法比较,结果显示,多重RT-PCR检测结果与常规单一RT-PCR的结果符合率均为100%。综上,本试验建立了能同时检测PDCoV,PEDV和TGEV的三重RT-PCR方法,为临床上这3种疫病的快速检测和流行病学调查奠定了基础。     

Impact of porcine group A rotavirus co-infection on porcine epidemic diarrhea virus pathogenicity in piglets

Porcine epidemic diarrhea virus (PEDV) and porcine group A rotavirus (PGAR) are the main causative agents of acute diarrhea in piglets. In South Korea, PGAR is prevalent in piglets naturally infected with PEDV. Piglets naturally co-infected with PEDV and PGAR appeared to have severe and prolonged diarrhea that was distinct from that commonly observed. The aim of this study was to determine the impact of PGAR co-infection on PEDV pathogenicity in piglets. Thirty-six colostrum-deprived, one-day old, Large White-Duroc crossbred pigs were randomly divided into four equal groups: PEDV, PEDV/PGAR, PGAR, and control groups. The piglets were euthanized at 1, 2, or 3 days post-inoculation (DPI) to measure the villous height:crypt depth (VH:CD) ratio and to collect fecal samples for RT-PCR and virus isolation. No significant differences in mean VH:CD ratio and clinical symptoms (diarrhea, vomiting, dehydration, and anorexia) were observed between the PEDV/PGAR-infected and PEDV-infected groups of piglets at 1, 2 and 3 DPI; however, at 2 and 3 DPI, PGAR was detected in all fecal samples by RT-PCR and virus isolation. These findings failed to detect any interaction between PEDV and porcine rotavirus in the small intestines of piglets, suggesting that concurrent infection of PGAR may not synergistically enhance intestinal villous atrophy of piglets with PEDV disease. We propose that the severe diarrhea exhibited in PEDV and PGAR co-infected piglets may be more associated with the immunity level of the host rather than to any synergistic effect of PGAR on PEDV enteritis.     

猪传染性胃肠炎病毒NASBA检测方法的建立

为建立猪传染性胃肠炎病毒(TGEV)NASBA的检测方法,本研究利用BioEdit和BlastN,根据GenBank中猪TGEV的S基因保守序列设计引物,建立了扩增TGEV的NASBA检测技术。利用该方法建立的反应体系在41℃反应2h即可得到有效扩增。实验结果表明:该方法对TGEV进行扩增获得约200bp特异性目的条带,而对CSFV、PRRSV、PCV-2、PPV、PEDV和ST细胞扩增结果均为阴性。NASBA的灵敏度高于普通RT-PCR,与病毒分离方法相当,可检测到5pg的核酸。该方法为TGEV的早期诊断提供了新途径。     

A capture-enzyme immunoassay for rapid diagnosis of transmissible gastroenteritis virus.

Two enzyme immunoassays (EIA) were developed for the detection of swine transmissible gastroenteritis virus (TGEV) antigens. The 2 EIAs used the same detecting system, a monoclonal antibody conjugated to horseradish peroxidase, but used different capture systems including a monoclonal antibody (m-EIA) or a polyclonal antibody (p-EIA). The EIAs were compared with the fluorescent antibody test (FAT) and electron microscopy (EM) for the detection of TGEV in intestinal samples of experimentally inoculated gnotobiotic piglets and of conventional diarrheic pigs submitted for diagnosis. In the gnotobiotic piglets experimentally inoculated with TGEV, 81.8% (9/11) were positive for TGEV by p-EIA, and 72.7% (8/11) were positive by m-EIA. In comparison, 81.8% (9/11) were positive by FAT and 27.2% (3/11) were positive by EM. Three noninfected controls were negative by all tests. In the diagnostic samples, 86.0% (43/50) were positive by p-EIA, 68.2% (30/44) were positive by m-EIA, 28.6% (14/49) were positive by IFA, and 38.0% (19/50) were positive by EM. The m-EIA had a higher agreement with FAT and EM than did p-EIA.     

Multiplex PCR for rapid detection of pseudorabies virus, porcine parvovirus and porcine circoviruses

A multiplex PCR (mPCR) assay was developed and subsequently evaluated for its effectiveness as a means to simultaneously detect multiple viral infections of swine. Specific primers for each of four common DNA viruses, namely, pseudorabies virus (PRV), porcine circovirus type I (PCV1), porcine circovirus type II (PCV2), and porcine parvovirus (PPV), were used for testing procedure. The assay was shown to be highly sensitive in that as little as 10(-4) ng of each of the respective amplicons (approximately equal to 10,000 molecules) was detected when a composite of all four viruses (including both field and gene-deleted permutations of PRV) was tested as a single sample. It was also effective for detecting one or more of these same viruses in various combinations in specimens including lymph nodes, lungs, spleens, and tonsils collected from clinically ill pigs, and in specimens in spleen collected from aborted fetuses. The relative efficiency (compared to performing separate assays for each virus) and apparent sensitivity of mPCR suggest its potential application for routine molecular diagnostic purposes.     

猪流行性腹泻病毒RT-LAMP检测方法的建立与应用

针对猪流行性腹泻病毒(PEDV)的M基因设计LAMP引物,对反应体系的条件优化并进行特异性及敏感性等试验。结果显示:该方法在60℃下恒温扩增60min,使PEDV的M基因得到了高效率特异性扩增。本试验方法特异性好,与猪瘟病毒(CSFV)、猪繁殖与呼吸综合征病毒(PRSSV)、猪圆环病毒2型(PCV-2)、猪细小病毒(PPV)及猪伪狂犬病病毒(PRV)等无交叉反应,同时也具有较好的灵敏性,最低检测分子拷贝数为1.0×102 copies/μL。反应结束后加入SYBR GreenⅠ在紫外灯下观察颜色变化,结果显示阳性扩增产物呈现绿色荧光。结果表明:该LAMP检测方法特异性强,灵敏度高,操作便捷,适于临床检测PEDV。     

Coronavirus infection in mink (Mustela vison). Serological evidence of infection with a coronavirus related to transmissible gastroenteritis virus and porcine epidemic diarrhea virus.

Antibodies to a transmissible gastroenteritis virus (TGEV)-related coronavirus have been demonstrated in mink sera by indirect immunofluorescence, peroxidase-linked antibody assays and immunoblotting. This is the first serological evidence of a specific coronavirus infection in mink. The putative mink coronavirus (MCV) seems to be widespread in the Danish mink population with a prevalence approaching 100%. Analysis by immunoblotting has shown that MCV is closely related to TGEV by the spike (S), matrix (M) and nucleoprotein (N) polypeptides. Furthermore, antibodies to MCV also cross-reacted with N and M polypeptides of porcine epidemic diarrhea virus (PEDV). Thus MCV may occupy an intermediate position between the TGEV group of coronavirus and PEDV. The possibility that MCV may be associated with syndromes of acute enteritis in preweaning mink is discussed.     

An ELISA for the detection of serum antibodies to both transmissible gastroenteritis virus and porcine respiratory coronavirus.

A competition ELISA utilizing a mAb directed towards a peplomer protein epitope common to TGEV, PRCV and related feline and canine coronaviruses is described.     

猪流行性腹泻病毒胶体金检测方法的建立

应用胶体金免疫层析技术,建立了一种快速检测猪流行性腹泻病毒(PEDV)的方法。采用柠檬酸三钠还原法制备胶体金颗粒,标记纯化的抗猪流行性腹泻病毒的单克隆抗体m Ab-PEDV1C12和(m Ab)-PEDV2C11,并将m Ab-PEDV2C11和羊抗鼠Ig G抗体喷在硝酸纤维素膜上分别作为检测线和质控线,对pH值、抗体浓度、封闭时间等条件摸索与优化。测试结果表明,该猪流行性腹泻病毒快速检测试纸条的检测下限达到310个TCID50的病毒量,检测时间为10 min,批内和批间重复性为100%。结论:该方法使用简单快速,适合猪场检测猪流行性腹泻病毒。     

RT-PCR检测猪传染性胃肠炎病毒方法的建立

猪传染性胃肠炎 ( TGE)是一种以严重腹泻、呕吐和脱水为临床特征的高度接触性传染病 ,属于国际兽疫局 ( OIE)法典中 B类疫病必检的猪传染病。TGEV是一种有囊膜的正链 RNA冠状病毒。目前检测 TGEV的方法主要有中和试验、免疫荧光抗体试验、酶联免疫吸附试验和电镜技术 ,这些方法对于检测 TGEV和防制 TGE起到了重要作用 ,但也存在特异性不强、灵敏性差、耗时长等缺点。c DNA探针、RT- PCR近年来已成为国际上用于检测病原微生物的主要方法。由于 c DNA探针与临床样品中非相关核酸有一定的非特异性结合 ,尤其是检测粪便、尿液等…     

环介导等温扩增技术快速检测猪流行性腹泻病毒

为建立一种快速、灵敏的检测猪流行性腹泻病毒(PEDV)的环介导等温扩增(LAMP)检测方法,本研究针对PEDV的NP基因设计LAMP引物,对反应体系优化并进行特异性及敏感性等试验.结果表明,该方法在65℃下恒温扩增60 min,经SYBR Green Ⅰ染色后仅肉眼观察即可判定结果.该方法特异性好,与传染性胃肠炎病毒、猪轮状病毒、猪瘟病毒及大肠杆菌等无交叉反应,对重组质粒最低检测限度为16拷贝/μL,灵敏度高于普通PCR.该LAMP检测方法特异性强,灵敏度高,操作方便,适于临床检测PEDV.     

检测猪传染性胃肠炎病毒Taq Man荧光定量RT-PCR方法的建立与初步应用

据GenBank登录的猪传染性胃肠炎病毒(TGEV)N基因的保守区序列设计合成了引物和探针,对荧光定量RT-PCR的反应条件进行了优化,建立了一种特异、灵敏、快速的TaqMan荧光定量RT-PCR方法来检测TGEV。与国外进口的An imal Genetics公司生产TGEV抗原快速检测试剂盒进行比较,符合率达到100%;与常规RT-PCR检测方法相比,灵敏度高100倍。用该方法对辽宁、山东、福建等地的送检疑似病料进行了检测,结果阳性率为24%。试验证明,所建立方法适用于猪传染性胃肠炎病毒的分子诊断、流行病学调查等相关研究。     

猪传染性胃肠炎病毒重组N蛋白抗原间接ELISA抗体检测方法的建立

本研究以纯化的原核表达猪传染性胃肠炎病毒N蛋白为诊断抗原，建立了猪传染性胃肠炎病毒抗体检测的间接ELISA诊断方法，将其命名为mTGE-ELISA。该抗原不与其他常见10种猪病的阳性血清发生交叉反应。批内和批间重复性试验的变异系数均小于15％；对仔猪免疫后不同时间的血清检测结果表明mTGE-ELISA与纯化病毒ELISA符合率达95．0％；mTGE-ELISA相对于VN试验的敏感性为96．3％、特异性为92．2％：现地试验中，mTGE-ELISA与Svanova TGEV／PRCV antibody diagnosis Kit的符合率达87．0％，通过中和试验复核结果表明，mTGE-ELISA的假阳性低于Svanova TGEV／PRCV antibody diagnosis Kit。本试验建立的mTGE-ELISA诊断方法具有良好的敏感性和特异性，为免疫猪群抗体监测和TGE流行病学调查提供了一种快速、简便的血清学诊断方法。     

Monoclonal antibody-based immunohistochemical detection of porcine epidemic diarrhea virus antigen in formalin-fixed, paraffin-embedded intestinal tissues.

An immunohistochemistry technique was developed for the diagnosis of porcine epidemic diarrhea virus (PEDV). The technique was tested on formalin-fixed, paraffin-embedded intestinal tissues from piglets naturally infected with PEDV. Five different monoclonal antibodies (MAbs) were tested in this study. PEDV antigen was consistently detected in the PLP (4% paraformaldehyde, 100 mM L-lysine dihydrochloride, 10 mM sodium m-periodate in phosphate-buffered saline)-fixed PEDV-infected Vero cells or formalin-fixed, paraffin-embedded intestinal tissues from piglets naturally infected with PEDV. The C9-2-2 MAb gave the strongest reactivity and least background staining, detecting 10 of 10 infected pigs. The positive reaction was cytoplasmic. Positive enterocytes were distributed over the tip and along the sides of atrophied or fused villi in the jejunum and ileum. Positive-staining cells were not detected in the crypts. No staining was observed in cecum and colon. No positive cells were observed when the C9-2-2 MAb was reacted with the tissue sections from noninfected piglets or from transmissible gastroenteritus virus (TGEV)- and rotavirus-infected piglets. The selected anti-PEDV MAbs tested on formalin-fixed, paraffin-embedded tissue sections are useful for diagnosis when virus isolation is not available. This method would be of particular value in countries where both PEDV and TGEV are epizootic and would aid in differentiating between PEDV and TGEV infection.