Expression of Pseudorabies Virus gE Core Epitopes in Escherichia coli Strain BL21 and Utilization of Indirect PRV gE-ELISA

Pseudorabies virus glycoprotein E （PRV gE） has been recognized as a suitable diagnostic antigen for pseudorabies. In order to produce gE antigen in large quantities and at low cost, a gene fragment encoding PRV gE core epitopes was expressed in E. coli BL21 expression system. SDS-PAGE and Western Blotting revealed that the expression product in culture supematant of E. coli BL21 was a recombinant protein, approximately 51.8 Kd. At 5 h post-induction, protein concentration assay showed that the expression product amounted to 1.65 mg/ml, accounting for 24. 17% of total proteins in the culture supematant. An indirect PRV gE-ELISA was established by using the recombinant expression product as a coating antigen. Cross-reactivity assay showed that this antigen was PRV specific. In addition, the assay was consistently reproducible. Comparison of detection results of 240 serum samples between PRV gE-ELISA and a commercially available PRV diagnostic kit showed that there was no significant difference between these two methods （P 〉 0.05 ）.

JEV、PRRSV、PPV及PRV多重PCR检测方法的建立及应用

为了建立一种能快速鉴别猪日本脑炎病毒(JEV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪细小病毒(PPV)和猪伪狂犬病病毒(PRV)的准确、高效的多重常规PCR检测方法,针对JEV、PRRSV、PPV、PRV基因保守区域合成特异性引物,优化后获得最优反应条件,对该方法特异性、敏感性、重复性进行了测定,并应用该方法对临床样品进行初步应用。结果显示,该方法对JEV、PRRSV、PPV、PRV可进行特异性扩增,对混合阳性质粒检测下限达2×10^(6)copies/μL,对猪圆环病毒2型、猪瘟病毒、猪流行性腹泻病毒、猪丁型冠状病毒、猪传染性胃肠炎病毒等相关病毒均无扩增,且重复性良好。用该方法检测51份2021年采集的广西区内组织样品,检出JEV、PRRSV、PPV、PRV阳性率分别为7.84%、50.98%、5.88%、23.53%,且存在多重混合感染的情况。所建立的多重PCR方法具有良好的特异性、敏感性及重复性,可应用于临床常见猪繁殖障碍性病毒病的快速诊断和监测预警,为猪繁殖障碍性病毒病提供了诊断技术支持。

Pathogenicity of a currently circulating Chinese variant pseudorabies virus in pigs

AIM:To test the pathogenicity of pseudorabies virus(PRV)variant HN1201 and compare its pathogenicity with a classical PRV Fa strain.METHODS:The pathogenicity of the newly-emerging PRV variant HN1201 was evaluated by different inoculating routes,virus loads,and ages of pigs.The classical PRV Fa strain was then used to compare with HN1201 to determine pathogenicity.Clinical symptoms after virus infection were recorded daily and average daily body weight was used to measure the growth performance of pigs.At necropsy,gross pathology and histopathology were used to evaluate the severity of tissue damage caused by virus infection.RESULTS:The results showed that the efficient infection method of RPV HN1201 was via intranasal inoculation at 107 TCID50,and that the virus has high pathogenicity to 35-to 127-d old pigs.Compared with Fa strain,pigs infected with HN1201 showed more severe clinical symptoms and pathological lesions.Immunochemistry results revealed HN1201 had more abundant antigen distribution in extensive organs.CONCLUSION:All of the above results suggest that PRV variant HN1201 was more pathogenic to pigs than the classical Fa strain.

Detection of Pseudorabies Virus Antibodies in Human Encephalitis Cases

Pseudorabies virus(PRV),a veterinary pathogen that infects domestic animals as well as wild animals such as wild boar and feral swine,was recently reported to infect human and led to endophthalmitis and encephalitis.A retrospective seroepidemiologic survey was conducted using 1,335 serum samples collected from patients with encephalitis and ELISA positive rates were 12.16%,14.25%,and 6.52%in 2012,2013,and 2017,respectively.

Microarray-Based Detection and Differentiation of Virulent and Attenuated Pseudorabies Virus

DNA microchip used in this study was formed from miniature arrays of pseudorabies virus （PrV） gene-specific probes immobilized on a glass surface. Hybridization using DNA microchip （microarrays） was used for differentiation between virulent and attenuated PrV. The presence of four gene segments （gB, gD, gE~, and gE ） encoding conservative glycoprotein B （gB）, D （gD）, and E （gE） of PrV was monitored using multiplex PCR. The amplicons were labeled with Cy5 or Cy3 dyes followed by hybridization to the gene-specific capture probes on the microchip. The presence of gD and gB, gE~ gene fragments was shown in virulent （gE~ genotype） and attenuated PrV （gE genotype）, whereas gE- gene （deleted domain in gE gene） was demonstrated only in virulent, not in attenuated, virus. No cross-hybridization was observed when fluorescence labeled-PCR products of PrV were hybridized using capture probes of related viruses, such as porcine respiratory and reproductive syndrome virus （PRRSV）, porcine parvovirus （PPV）, Japanese encephalitis virus （JEV）, and porcine circovirus type 2 （PCV-2）. The assay was 10 times sensitive than gD gene-specific PCR. Overall, the results of this study suggested that the microarray might be very useful for detection and differentiation of virulent PrV from attenuated one.

Establishment and Application of a SYBR Green I Real-time Quantitative PCR Assay for the Detection of LAT Gene of Pseudorabies Virus in Bama Miniature Pigs

[ Objective] This study aimed to establish a rapid, sensitive and specific SYBR Green I real-time quantitative PCR assay for the detection of latent pseudorabies virus （PRV） infection. [ Method ] SYBR Green I real-time quantitative PCR conditions and system for early detection of latent pseudorabies virus in- fection were optimized and compared with conventional PCR to investigate the sensitivity and specificity. Subsequently, the established assay was applied to detect different clinical samples. [ Result] The sensitivity of SYBR Green I real-time quantitative PCR assay （52 copies/μl） was 1 000 times higher than that of conven- tional PCR （5.2×1^04 copies/μl） and the detection time was shortened by 1/2. The established assay could be used to detect PRV but could not be used to detect PCV2, PPV, CSFV or PRRSV. Various tissues were collected from Bama miniature pigs with latent PRV infection under sterile conditions for real-time PCR detection. Results showed that viral copy number in the brain, nasal swab, inguinal lymph node, liver, lung and spleen was above 20, while PRV was not detected in the kidney and heart tissues. [ Conclusion] The established SYBR Green I real-time quantitative PCR assay for PRV/.AT detection was specific, sensitive and rapid, which could be used for pathogen monitoring, epidemiological investigation and quantitative study of PRV.

Subculturing cells have no effect on CRISPR/Cas9-mediated cleavage of UL30 gene in pseudorabies virus

CRISPR/Cas9-mediated genome editing can inhibit virus infection by targeting the conserved regions of the viral genomic DNA. Unexpectedly, we found previously that pseudorabies virus(PRV) could escape from CRISPR/Cas9-mediated inhibition.In order to elucidate whether the escape of PRV from Cas9-mediated inhibition was due to cell deficiencies, such as genetic instability of sgRNA or Cas9 protein, the positive cells were passaged ten times, and PRV infection in the sgRNA-expressing cells was evaluated in the present study. The results showed that subculturing cells has no effect on Cas9-mediated cleavage of PRV. Different passages of PX459-PRV cells can stably express sgRNA to facilitate Cas9/sgRNA cleavage on the UL30 gene of PRV, resulting in a pronounced inhibition of PRV infection. Studies to elucidate the mechanism of PRV escape are currently in progress.

Development of PPA-ELISA for Detecting Antibodies against Porcine Pseudorabies Virus Using Truncated Recombinant Glycoprotein gD Expressed in E.coli

The purpose of this study was to develop a method for detecting antibodies against porcine pseudorabies virus （PRV）. According to the published genomic sequence of PRV SA strain, an approximately 1 070-bp gD gene fragment was amplified by PCR. The PCR products were cloned into the prokaryotic expression vector pET30a and the positive recombinant plasmid was transformed into E. coli BL21. Through induction with IPTG, the recombinant gD protein was expressed as inclusion bodies. As analyzed by western blot assay, the purified recombinant gD protein had good antigenicity and high specificity. Using the purified gD protein as coating antigen and horseradish peroxidase labeled staphylococcal protein A （PPA） as secondary antibody, we developed a PPA-ELISA for detecting antibodies against porcine PPV. No cross-reaction with the positive sera against seven common pathogens in pigs including classical swine fever virus, porcine parvovirus, porcine reproductive and respiratory syndrome, Japanese encephalitis virus, porcine circovirus type 2, porcine epidemic diarrhea virus, transmissible gastroenteritis virus was observed. The repeatability test showed that the intra- and inter-assay coefficients of variation were lower than 5% and 10%, respectively. Compared with the ELISA gD antibody test kit produced by IDEXX, the coincidence, sensitivity and specificity of the developed PPA-ELISA were 92.0%, 95.1% and 88.1%, respectively. The developed PPA-ELISA had good repeatability, sensitivity and specificity and was a rapid and simple serological method for surveillance of PRV antibodies in pig herds as well as for rapid diagnosis and epidemiological investigation of PRV infection.

Characterization of Synonymous Codon Usage Bias in the Pseudorabies Virus US1 Gene

In the present study, we examined the codon usage bias between pseudorabies virus (PRV) US1 gene and the US1-like genes of 20 reference alphaherpesviruses. Comparative analysis showed noticeable disparities of the synonymous codon usage bias in the 21 alphaherpesviruses, indicated by codon adaptation index, effective number of codons (ENc) and GC3s value. The codon usage pattern of PRV US1 gene was phylogenetically conserved and similar to that of the US1-like genes of the genus Varicellovirus of alphaherpesvirus, with a strong bias towards the codons with C and G at the third codon position. Cluster analysis of codon usage pattern of PRV US1 gene with its reference alphaherpesviruses demonstrated that the codon usage bias of US1-like genes of 21 alphaherpesviruses had a very close relation with their gene functions. ENc-plot revealed that the genetic heterogeneity in PRV US1 gene and the 20 reference alphaherpesviruses was constrained by G+C content, as well as the gene length. In addition, comparison of codon preferences in the US1 gene of PRV with those of E. coli, yeast and human revealed that there were 50 codons showing distinct usage differences between PRV and yeast, 49 between PRV and human, but 48 between PRV and E. coli. Although there were slightly fewer differences in codon usages between E.coli and PRV, the difference is unlikely to be statistically significant, and experimental studies are necessary to establish the most suitable expression system for PRV US1. In conclusion, these results may improve our understanding of the evolution, pathogenesis and functional studies of PRV, as well as contributing to the area of herpesvirus research or even studies with other viruses.

Isolation and Identification of a Porcine Pseudorabies Virus Strain in Taizhou City

In this study, the liver, kidney and spleen tissues were collected from pigs with suspected PR in a pig farm in Jiangyan District, Taizhou City for virus isolation and identification. The isolated virus was inoculated onto PK15 monolayer cells. The virus culture was collected to extract genomic DNA for PCR assay and indirect immunoinfluscent assay. The results showed that the isolated virus was porcine pseudorabies virus, which was named TAIZ130417. The growth titer of the isolated virus reached 10 8.12 TCID 50 /ml on PK15 cells. Rabbits inoculated with the isolated virus soon exhibited pseudorabies symptoms such as itching and eventually died. The results provided reference for in-depth research and scientific prevention and control of pseudorabies.

黄芩多糖对PRV感染猪睾丸细胞的作用及其差异基因表达分析

为研究黄芩多糖对伪狂犬病毒(PRV)感染猪睾丸(ST)细胞的作用并筛选与调控相关的差异基因,本试验建立PRV感染ST细胞模型,将其分为预防、治疗和杀毒模式,分别使用不同浓度的黄芩多糖溶液进行处理,每个模式下设立空白对照组和PRV对照组。采用CCK-8法检测黄芩多糖对ST细胞存活率的影响,显微镜观察各组细胞形态,ELISA检测IFN-γ、IFN-α和TNF-α细胞因子含量;在24 h时提取RNA进行转录组测序,分析其差异表达基因并进行GO功能和KEGG通路分析。结果显示,PRV感染ST细胞出现病变。与PRV对照组相比,黄芩多糖浓度为97.66μg/mL时,3种模式中细胞存活率均极显著升高(P<0.01),细胞病变减轻,IFN-γ和IFN-α含量均极显著提高(P<0.01),TNF-α含量极显著降低(P<0.01),治疗指数(TI)分别为2、4和4。治疗模式下,97.66μg/mL黄芩多糖处理组、空白对照组和PRV对照组比较共交集差异基因74个,其中SOCS3、VEGFA、ZBTB18、CLCN6、RSBN1、RBM47和TET2基因差异表达较为显著,差异表达基因显著富集到15条信号通路,PRV对照组与空白对照组和PRV对照组与黄芩多糖治疗组比较,差异表达基因主要分别涉及核糖体、内吞、MAPK、TNF和MAPK、mTOR、TLR等相关通路。结果表明,黄芩多糖对PRV感染ST细胞具有保护作用,其作用可能是通过调节TNF信号通路和TLR信号通路中SOCS3、CCL5、FOS、PIK3R1和MAP3K8等相关基因的表达来实现。本试验结果将为进一步探索黄芩多糖调控PRV感染宿主的作用机制提供理论依据。

Comparison on Detection Results of PRV Wild Virus Antibody Provided by Different Institutions

The detection results from different institutions were performed at the first stage of PRV wild virus antibody supervision in swine breeding. The serum samples were collected from 71 individuals and each individual was sampled twice at one week interval. The results showed that the positive coincidences for gE antibody between two institutions were 35.71% and 45.45 % ：espectively, with the total detection coincidences of 87.32% and 91.55% correspondingly. The positive coincidences for gE antibody between the two detections of each institution were 40.00% and 75.00% respectively, with the total detection coincidences of 87.32% and 97.18% correspondingly. It indicates that it is very necessary to screen the detection institution at the first supervision stage of PRV wild vires for swine population.

ASFV、PRV和PCV2多重荧光定量PCR检测方法的建立和应用

非洲猪瘟病毒(ASFV)、伪狂犬病毒(PRV)、猪圆环病毒2型(PCV2)是危害养猪业的3种重要病毒,但目前国内外尚无可同时检测这3种病原的方法。为建立一种可同时检测上述3种病原的方法,本研究以ASFV的B646L基因、PRV的gE基因及PCV2的rep基因为靶基因,采用Prime 3 web软件分别设计特异性引物和探针。采用相应引物分别构建上述3种靶基因的重组质粒,经测序鉴定后分别作为质粒标准品,并均稀释到1×105拷贝/μL后按照体积比1∶1∶1混匀后作为模板,采用方阵法对引物、探针、酶和各反应条件等的优化,初步建立ASFV、PRV和PCV2多重荧光定量PCR检测方法。结果显示,该方法标准曲线Ct值与相应质粒标准品浓度均存在良好的线性关系,相关系数(R2)均大于0.99。利用该方法同时检测猪瘟病毒(CSFV)、猪繁殖与呼吸综合征病毒(PRRSV)、口蹄疫病毒(FMDV)、猪细小病毒(PPV)、牛病毒性腹泻病毒(BVDV)、传染性胃肠炎病毒(TGEV)等病原,结果显示,本实验建立的该方法仅特异性扩增ASFV、PRV和PCV2,与其他病原均无交叉反应,特异性强;分别利用该方法与已公布的中华人民共和国农业农村部公告第172号中ASFV荧光定量PCR检测方法、PCV2荧光定量PCR方法(GB/T 35901-2018)、PRV荧光定量PCR检测方法(GB/T 35911-2018)对10倍倍比稀释(1.0×10^(4)拷贝/μL~1.0×10_(0)拷贝/μL)后的pUC57-ASFV-B646L、pUC57-PRV-gE、pGEMT-PCV2-rep质粒标准品1∶1∶1的混合物检测,结果显示该方法对3种质粒标准品的最低检测限均为10拷贝/μL,相同或略高于上述各病原的单一qPCR检测结果,表明本实验建立的该方法敏感性较高;选取3个稀释度的质粒标准品分别按1∶1∶1比例混合后进行组内和组间重复性试验,结果显示组内组间变异系数均小于3%,重复性好。利用本实验建立的方法和上述3种病原标准检测方法对114份临床样品检测,结果显示,本实验建立的方法对ASFV、PRV和PCV2检测的的阳性样品数分别为10份、10份和42份,未发现混合感染现象,与3种病原的标准方法相比符合率均为100%。以上结果表明,本研究建立的ASFV、PRV和PCV2多重荧光定量PCR方法特异性强、敏感性高、重复性好,可用于这3种常见猪病的鉴别诊断和流行病学调查。

Isolation and Identification of Sheep Pseudorabies Virus

In a sheep farm with mixed culture of pig and sheep in Shandong Province,sheep were attacked by a disease featured by foaming at the mouth,neurological symptoms and partial hair slip of legs,and the mortality of the disease was as high as 100%.In order to determine the pathogen,dead sheep were analyzed through pathogen isolation,PCR assay and direct immunofluorescence identification,and the pathogen was confirmed as pseudorabies virus（PRV）.Sequencing results showed that the g E gene of the isolated strain shared the homology of 97%-99% with the nucleotide sequence of known PRV genome in the NCBI databases,suggesting the isolate was PRV.The virus had obvious cytopathic effect through BHK cell line passage till the seventh generation,and the amount of half virus tissue cell infection（TCID50） was 1×107.5/m L following ReedMuench method.Two healthy sheep with the body weight of 20 kg were injected with the viral fluid of the isolate,and typical symptoms of pseu-dorabies（PR） were observed after 4 d.According to clinical symptoms and PCR diagnosis results,the epidemic situation of sheep farm was effec-tively controlled through comprehensive measures such as eliminating swinery in the farm,strengthening disinfection of pigsty,injecting sick sheep with pseudorabies serum,supplementing healthy sheep herb with antivirus traditional medicine Qiqing Baidu granule.

Tn7-mediated Introduction of DNA into Bacmid-cloned Pseudorabies Virus Genome for Rapid Construction of Recombinant Viruses

lacZα-mini-attTn7 was inserted into the intergenic region between the gG and gD genes in a PRV bacterial artificial chromosome (BAC) by homologous recombination in E. coli. The resulting recombinant BAC (pBeckerZF1) was confirmed by PCR and sequencing. Green fluorescent protein (GFP) gene was then transposed into pBeckerZF1 by transposon Tn7 to generate pBeckerZF2. Recombinant viruses vBeckerZF1 and vBeckerZF2 were generated by transfection with the corresponding BAC pBeckerZF1 or pBeckerZF2. The titers and cytopathic effect (CPE) observed for by vBeckerZF1 and vBeckerZF2 was comparable to that of the parental virus vBecker3. vBeckerZF2 was serial passaged for five rounds in cell culture, and the mini-Tn7 insertion was stably maintained in viral genome. These results show that recombinant viruses can be rapidly and reliably created by Tn7-mediated transposition. This technology should accelerate greatly the pace at which recombinant PRV can be generated and, thus, facilitate the use of recombinant viruses for detailed mutagenic studies.

Kaempferol inhibits Pseudorabies virus replication in vitro through regulation of MAPKs and NF-κB signaling pathways

Pseudorabies virus(PRV),in the family Herpesviridae,is a pathogen of Aujeszky’s disease,which causes great economic losses to the pig industry.Recent outbreaks of Pseudorabies imply that new control measures are urgently needed.The present study shows that kaempferol is a candidate drug for controlling PRV infection,as it possesses the ability to inhibit PRV replication in a dose-dependent manner in vitro.Kaempferol at a concentration of 52.40μmol L^(-1) could decrease PRV-induced cell death by 90%.With an 50%inhibitory concentration(IC50)value of 25.57μmol L^(-1),kaempferol was more effective than acyclovir(positive control)which has an IC50 value of 54.97μmol L^(-1).A mode of action study indicated that kaempferol inhibited viral penetration and replication stages,decreasing viral loads by 4-and 30-fold,respectively.Addition of kaempferol within 16 h post infection(hpi)could significantly inhibit virus replication,and viral genome copies were decreased by almost 15-fold when kaempferol was added at 2 hpi.Kaempferol regulated the NF-κB and MAPKs signaling pathways involved in PRV infection and changed the levels of the target genes of the MAPKs(ATF-2 and c-Jun)and NF-κB(IL-1α,IL-1βand IL-2)signaling pathways.The findings of the current study suggest that kaempferol could be an alternative measure to control PRV infection.

Design of live-attenuated animal vaccines based on pseudorabies virus platform

Pseudorabies virus(PRV)is a double-stranded DNA virus with a genome approximating 150 kb in size.PRV contains many non-essential genes that can be replaced with genes encoding heterogenous antigens without affecting viral propagation.With the ability to induce cellular,humoral and mucosal immune responses in the host,PRV is considered to be an ideal and potential live vector for generation of animal vaccines.In this review,we summarize the advances in attenuated recombinant PRVs and design of PRV-based live vaccines as well as the challenge of vaccine application.

辣蓼黄酮正丁醇部位对PRV感染3D4/2细胞氧化应激相关因子水平的影响

【目的】探究辣蓼黄酮正丁醇部位(N-butanol fraction of Polygonum hydropiper flavonoids,FNB)对猪伪狂犬病毒(Pseudoabies virus,PRV)体外感染猪肺泡巨噬细胞(3D4/2细胞)氧化应激相关因子的影响,旨在初步分析FNB的抗氧化效果。【方法】采用10-1至10-10浓度PRV体外感染猪肾细胞(PK15细胞),计算病毒半数组织培养感染剂量(TCID50);将3D4/2细胞分为BC组、DMSO组、PRV组、FNB 1、FNB2和FNB3组,BC组用DMEM培养液处理,其余各组用感染复数(multiplicity of infection,MOI)=0.1 RPV处理,孵育2 h后,PRV组添加DMEM培养液,DMSO组及FNB1、FNB2、FNB3组分别添加0.05%DMSO及12.5、25、50μg/mL FNB的DMEM培养液。培养4、8、12、24 h后,分别收取各组细胞培养液上清和细胞,通过试剂盒测定细胞培养液上清中一氧化氮(NO)的含量、细胞内活性氧(ROS)、诱导型一氧化氮合酶(iNOS)、黄嘌呤氧化酶(XOD)、髓过氧化物酶(MPO)的活性和丙二醛(MDA)的含量。【结果】PRV的TCID50为10-8.25/0.1 mL;与BC组相比,PRV组上清中NO水平在4、8 h时极显著降低(P<0.01),在12、24 h时极显著升高(P<0.01),细胞内ROS在4 h时显著降低(P<0.05),8~24 h时显著或极显著升高(P<0.05;P<0.01),iNOS和XOD活性在8~24 h时显著或极显著升高(P<0.05;P<0.01),MPO活性在4~24 h时显著升高(P<0.05),MDA含量在4 h时显著降低(P<0.05),12~24 h时显著升高(P<0.05)。与PRV组相比,FNB2组NO含量在4~8 h时显著或极显著升高(P<0.05;P<0.01),在12 h时显著降低(P<0.05),FNB3组在24 h时极显著升高(P<0.01);细胞内ROS水平在4 h时极显著升高(P<0.01),8~24 h时极显著降低(P<0.01);FNB1组iNOS活性在4 h时显著升高(P<0.05),3个FNB组iNOS活性在8~24 h时显著或极显著升高(P<0.05;P<0.01),MPO和XOD活性在4~24 h时显著或极显著降低(P<0.05;P<0.01),MDA含量在4 h时升高,8 h时FNB2、FNB3组MDA含量显著降低(P<0.05),24 h时FNB1、FNB2组MDA含量显著降低(P<0.05)。【结论】FNB可以通过干预氧化应激相关因子的分泌调节细胞氧化应激水平,维持氧化与抗氧化的平衡,结果可为辣蓼黄酮正丁醇部位的开发应用提供理论依据。

湖羊感染羊源性伪狂犬病病毒致病特征的研究

为探讨羊源性伪狂犬病病毒分离株SH1407对湖羊的致病性。将7只健康湖羊随机分成试验组和对照组,其中试验组5只,对照组2只。用分离株SH1407对试验组湖羊进行人工攻毒,取发病死亡羊内脏组织用于组织病理学检查和免疫组化分析。湖羊在攻毒后3 d开始出现症状,第4 d症状进一步加剧,表现为局部奇痒、体温升高、精神沉郁、食欲废绝等症状,4只发病死亡,存活1只,死亡率达到80%。剖检主要表现为脑膜充血,肺淤血,轻度实变。病理组织学检查:大脑、延髓神经元变性,细胞核溶解、消失,呈病理性细胞凋亡;肺脏呈间质性肺炎病变;脾脏、肾脏出血。免疫组化染色显示,PRV在肝脏、肺脏、大脑、脾脏等组织器官广泛存在,病毒在肝脏中主要存在于库弗氏细胞中,在肺脏中主要存在于Ⅱ型肺泡细胞中,在脾脏中主要存在于巨噬细胞、单核细胞中,而在脑组织中,神经元呈现较强的信号,说明病毒主要存在于神经细胞中。实时荧光定量PCR测定内脏器官病毒载量,肝脏、脾脏、肺脏和脑组织中PRV大量增值,其中PRV在脑组织中大量增值导致中枢神经严重的病理改变。