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1.
Swine herds in the US have experienced recent outbreaks of a severe form of porcine reproductive and respiratory syndrome (designated acute or atypical PRRS) characterized by abortion and high mortality in pregnant sows. Most of the affected herds had been vaccinated with modified live-vaccines (MLVs) against PRRS. To explore the possible mechanism of the emergence of acute PRRS, the open reading frame 5 (ORF5) gene encoding the major envelope protein (GP5) of acute PRRSV isolates was characterized. The complete ORF5 gene of eight acute PRRSV isolates from herds experiencing acute PRRS outbreaks in Iowa and North Carolina was amplified and sequenced. Sequence analyses revealed that these acute PRRSV isolates shared 88-95% nucleotide and 88-96% amino acid sequence identities to each other, 87-97% nucleotide and 84-96% amino acid sequence identities with other North American PRRSV isolates and the MLVs. Most of the amino acid substitutions locate in the putative signal sequence and two short hypervariable regions at the amino terminus. The ORF5 gene sequence of the acute PRRSV isolate 98-37120-2 from a non-vaccinated swine herd in Iowa is very closely related to that of the RespPRRS MLV, with 97% nucleotide and 96% amino acid sequence identities. Phylogenetic analysis revealed that all eight acute PRRSV isolates are clustered within the North American genotype. Several minor branches that are not associated with geographic origins were also identified within the North American genotype. One acute PRRSV isolate (98-37120-2) is clustered with the RespPRRS MLV and several Danish isolates that were confirmed to be derived from the RespPRRS MLV. The ORF5 gene sequences of other seven acute isolates are more related to those of several earlier PRRSV isolates and the PrimePac MLV than to that of the RespPRRS MLV. Our results showed that the acute PRRSV isolates analyzed in this study differed from each other in ORF5 genes, although they all clustered within the North American genotype. The data from this study do not fully support the hypothesis that the emergence of acute PRRS is due to reversion of MLVs to a pathogenic phenotype, as only one of the eight acute isolates was shown to be very closely related to the RespPRRS MLV.  相似文献   

2.
为研究宁夏地区猪繁殖与呼吸综合征(PRRS)的流行规律,应用RT-PCR的方法从PRRSV分离株GP3蛋白中扩增出ORF3基因cDNA片段。结果显示,ORF3基因全长765 bp,编码254个氨基酸,与北美型毒株VR-2332的同源性达到85%以上,与欧洲型毒株LV的同源性低于60%,与国内近3年主要流行毒株JXA1、HEB1、HUB2亲缘性较近。对PRRSV分离株的亲水性分析表明,GP3蛋白的前57位氨基酸为疏水性信号肽序列;对PRRSV分离株GP3蛋白抗原表位分析表明,与国内外其他毒株抗原表位预测的结果基本一致,说明PRRSV分离株GP3蛋白具有与其他毒株相近的抗原特性。  相似文献   

3.
为了弄清河北省秦皇岛、唐山、廊坊、邯郸等部分地区流行的猪繁殖与呼吸综合征病毒（PRRSV）的ORF5和Nsp2基因变异情况,对采自以上地区在2007—2010年期间的临床发病猪肺组织,提取其RNA,通过RT—PCR扩增样本中PRRSV的ORF5和Nsp2基因,对目的基因测序,并以VR-2332、CH—la、MLV、LV、HB-1、HB-2、JXA1、HUB1、HEB1等毒株为参考序列,进行序列分析和进化树分析。扩增出42个ORF5基因,14个Nsp2基因,通过完整的ORF5和部分Nsp2基因序列比较分析发现所有毒株均为美洲型,且大多数毒株与国内2006—2007年间分离的JXA1、HUB1、HEB1等高致病力毒株同源关系很近。42个ORF5基因编码的氨基酸序列分析表明GP5蛋白的糖基化位点数量和位置已发生变异,主要中和表位存在氨基酸变异（L／F^35→I^39）,与毒力相关的13位和151位点为强毒株的氨基酸特性（R^13、R^151）。14个Nsp2基因推导的氨基酸系列比较发现,1株PRRSV Nsp2基因未发生缺失突变,而剩余的13个毒株Nsp2基因均发生了氨基酸缺失,在481位和532～560位2处分别缺失1和29个氨基酸。系统发育进化树结果显示河北部分地区流行株分为2个小分支,1个毒株与HB-1聚为1支;河北流行株的大多数毒株在另一个分支,与高致病力毒株JXA1等聚为一支。本研究结果揭示了河北省部分地区流行的PRRSV ORF5和Nsp2基因的变异特征,丰富了河北省的PRRSV分子流行病学资料,提示要针对ORF5和Nsp2基因的变异采取PRRSV的防控措施。  相似文献   

4.
参考GenBank发表的猪繁殖与呼吸综合征病毒(PRRSV ) JXA1的ORF5基因序列,设计并合成了一对引物,对分离自云南、浙江、山东、辽宁、黑龙江、天津、湖南等7省12株PRRSV分离株进行RT-PCR扩增,获得约773 bp的DNA片段,将其分别克隆至pGEM-T Easy载体中,并进行测序.应用DNAStar软件分析序列,并与VR-2332、CH-la、MLV、LV、BJ4、HB1、HuB2、JXA1等毒株ORF5序列进行比较,结果表明,分离株间的核苷酸同源性为91.9%～100%,氨基酸同源性为90.1%～100%;在美洲株遗传关系上又分为明显的2个群:12株分离株与HB1、HuB2、JXA1、CH-la亲缘关系比较近,处于一个亚群;VR-2332、MLV、BJ4处于另一个亚群.说明高致病PRRSV为我国PRRS主要流行病毒.  相似文献   

5.
Genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) has been based on ORF5/GP5 and ORF7/N protein variations. Complete viral genome studies are limited and focused on a single or a few set of strains. Moreover, there is a general tendency to extrapolate results obtained from a single isolate to the overall PRRSV population. In the present study, six genotype-I isolates of PRRSV were sequenced from ORF1a to ORF7. Phylogenetic comparisons and the variability degree of known linear B-epitopes were done considering other available full-length genotype-I sequences. Cytokine induction of all strains was also evaluated in different cellular systems. Non structural protein 2 (nsp2) was the most variable part of the virus with 2 out of 6 strains harboring a 74 aa deletion. Deletions were also found in ORF3 and ORF4. Phylogenetic analyses showed that isolates could be grouped differently depending on the ORF examined and the highest similarity with the full genome cluster was found for the nsp9. Interestingly, most of predicted linear B-epitopes in the literature, particularly in nsp2 and GP4 regions, were found deleted or varied in some of our isolates. Moreover, 4 strains, those with deletions in nsp2, induced TNF-α and 3 induced IL-10. These results underline the high genetic diversity of PRRSV mainly in nsp1, nsp2 and ORFs 3 and 4. This variability also affects most of the known linear B-epitopes of the virus. Accordingly, different PRRSV strains might have substantially different immunobiological properties. These data can contribute to the understanding of PRRSV complexity.  相似文献   

6.
In 2006, highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) caused great economic losses emerged in China and continues to be a threat for the pig industry. B antigenic region (AR) ((37)SHL/FQLIYNL(45)) of GP5 was considered to be a major linear neutralizing AR in PRRSV classical strains. However, peptide-purified antibodies against this AR did not neutralize PRRSV in a recent report. Compared with classical PRRSV, one amino acid mutation (L/F(39)→I(39)) was found in B AR of HP-PRRSV. To study the ability of B AR of HP-PRRSV to induce neutralizing antibody (NA) in vitro and in vivo, rabbit antisera against B AR with and without the mutation and pig hyperimmune sera with high titer of NAs against HP-PRRSV were prepared. Immunofluorescence assays (IFA) showed that the two rabbit antisera both had reactivity to classical PRRSV CH-1a and HP-PRRSV HuN4 with no observable difference in IFA titer. However, antisera did not have neutralizing activity against classical PRRSV CH-1a and HP-PRRSV HuN4. No correlation was observed between the levels of anti-B AR peptide antibodies and NAs in pig hyperimmune sera that were detected by indirect ELISA and virus neutralization, respectively. B AR peptide-specific serum antibodies had no neutralizing activity and, GST-B fusion protein could not inhibit neutralization of NAs in pig hyperimmune sera. Based on these findings, we conclude that B AR of HP-PRRSV is not a neutralizing AR of HP-PRRSV GP5.  相似文献   

7.
参考Genbank发表的猪繁殖与呼吸综合征病毒（PKRSV）ATCC VR-2332的ORF5基因序列，设计并合成了一对引物．对来自福建、浙江、山东等地的PRRSV分离毒株进行RT-PCR扩增．获得约748bp的DNA片断，将其分别克隆入pMD18-T载体中，并进行测序。应用DNAStar软件分析所测序列，并与ATCCVR-2332、CH-1a、MLV、Lv等毒株的ORF5序列进行比较，结果表明：SHDl与F114、MLV、ATCCVR-2332同源性高达98．5％，与CH-1a同源性为91．0％，与其它毒株同源性为86．6％~88．4％；F114与MLV、ATCCVR-2332同源性为99．3％～99．7％．其余分离毒株在遗传关系上和CH-1a又分为明显的两个群．显示近年来各地PRRSV分离毒株与cH-1a株的遗传差异越来越大。  相似文献   

8.
本试验以辽宁地区某猪场猪繁殖与呼吸综合征(porcine reproductive and respiratory syndrome,PRRS)发病猪病料为材料,采用RT-PCR方法特异性扩增编码猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)GP5蛋白的ORF5基因全长cDNA,结果该分离株ORF5基因编码区长603bp,可编码200个氨基酸。与美洲型代表株VR2332、欧洲型代表株LV进行同源性比较,氨基酸同源性分别为89.5%和55.7%。推测该辽宁分离株属于美洲型。  相似文献   

9.
李彬  王豪男  彭忠  胡睿铭  吴斌 《中国畜牧兽医》2015,42(11):3026-3036
为了解当前猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)流行毒株的遗传变异情况,本研究对2013-2014年间来源于中国华中地区湖北、河南和湖南3省20个猪场65份疑似PRRSV感染的临床样品开展病毒分离工作,通过RT-PCR及间接免疫荧光试验进行鉴定,结果显示成功分离到4株PRRSV。通过测序获得它们的部分Nsp2氨基酸序列,经比对分析,确定分离毒株皆为变异毒株,并且与JXA1、TJ等高致病性毒株有相同的遗传特点,在Nsp2区域有30个氨基酸的不连续缺失。本研究将从临床样品中测序获得的23株PRRSV的GP5氨基酸序列与GenBank公布的有代表性的毒株序列进行遗传进化分析,结果显示所有毒株均为美洲型毒株,其中21株与高致病性变异毒株(JXA1、TJ和HUN4)同源性较高,同时在主要中和位点和N-糖基化位点存在部分氨基酸突变,另外两株与疫苗毒株RespPRRS MLV同源性较高。本试验结果表明,当前高致病性PRRSV依然是优势毒株,其GP5氨基酸突变频繁,不同地区流行毒株存在一定的遗传差异。  相似文献   

10.
为研究鲁豫冀地区猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)的遗传变异情况,对2006—2012年来自3省区发病猪场的42份样品进行PRRSV分离鉴定,并进行了生物学特性研究和PCR鉴定,结果显示先后分离到15株PRRSV。分别采用RT-PCR扩增其ORF5基因和部分Nsp2基因并测序,与GenBank中68个ORF5序列和40个Nsp2序列的推导氨基酸序列进行比对,遗传变异分析结果表明,15株分离株均属于美洲型毒株,其中13个毒株Nsp2基因推导的氨基酸序列均存在氨基酸的不连续缺失,其ORF5基因推导的氨基酸序列与JXA1株有较高的同源性(95.5%~97.5%);SDDY2007株与疫苗株RespPRRS MLV和VR2332株亲缘关系相近,处于同一个亚群中;而HN25-2009分离株Nsp2基因推导的氨基酸序列有30个氨基酸的特征性缺失,其ORF5基因推导的氨基酸序列的遗传进化分析结果显示该分离株处于VR2332所在亚群(氨基酸同源性97.5%),具有一定特殊性。本试验结果表明,2006—2012年高致病性PRRSV是鲁豫冀地区的优势流行毒株,且存在疫苗毒株,3省区流行毒株间有一定遗传差异,但无明显地域特征。  相似文献   

11.
The 23 open reading frame (ORF) 5 sequences of Korean type II porcine reproductive and respiratory syndrome virus (PRRSV) were collected from viremic sera from the (modified live vaccine) MLV-vaccinating and non-vaccinating farms from 2007 to 2008. The samples were phylogenetically analyzed with previous ORF5 sequences, including type I Korean PRRSV, and previously reported or collected sequences from 1997 to 2008. A MN184-like subgroup of type II Korean PRRSV was newly identified in the viremic sera collected from 2007 to 2008. And of the type I PRRSVs, one subgroup had 87.2~88.9% similarity with the Lelystad virus, showing a close relationship with the 27~2003 strain of Spain. The maximum parsimony tree of type II PRRSV from 1997 to 2008 showed that they had evolved to four lineages, subgroups 1, 2, 3 and 4. Most of the recently collected type II PRRSVs belonged to subgroup 4 (48%). The region of three B-cell epitopes and two T-cell epitopes of ORF5 amino acids sequences was considerably different from the MLV in subgroups 3 and 4. In conclusion, the existence of type I PRRSV, which was genetically different from Lelystad virus (Prototype of type I PRRSV), and heterologous type II PRRSVs of viremic pigs detected even in the MLV-vaccinating farms indicated the need for new vaccine approaches for the control of PRRSV in Korea.  相似文献   

12.
2005年-2010年我国部分地区PRRSV流行毒株的遗传变异分析   总被引：3，自引：0，他引：3  
为了掌握高致病性猪繁殖与呼吸综合征病毒(PRRSV)的变异情况,揭示该病的发生规律,根据GenBank登录的PRRSV基因序列设计引物,采用RT-PCR法对2005年-2010年间送检的282份病料进行了PRRSV核酸检测,对其中9份阳性样品进行了ORF5～7基因片段扩增和测序,所得序列与GenBank下栽的PRRSV...  相似文献   

13.
为了解广东省猪繁殖与呼吸综合征病毒(PRRSV)流行毒株ORF5基因遗传变异情况,采用RT-PCR对2018年采自广东部分地区疑似患有PRRS的猪肺组织样品进行PRRSV ORF5基因扩增以及克隆测序,并进行生物信息学分析。结果表明,成功扩增出18株PRRSV流行毒株的ORF5基因片段。ORF5基因序列分析表明,18株PRRSV流行毒株ORF5基因核苷酸同源性为83.7%~99.8%,PRRSV流行毒株与参考毒株的同源性为62.1%~99.8%。基于ORF5基因的遗传进化树分析表明,18株PRRSV流行株均为美洲型毒株。其中,10株与以JXA1为代表的高致病性毒株亲缘较近,2株与新型高致病性毒株FZ16A相似;1株与以NT1为代表的疫苗返强毒株亲缘较近,1株与以R98为代表的疫苗毒株亲缘性较近,4株与广东新报道的GM2和QYYZ毒株亲缘性较近。DNA推导氨基酸序列分析表明,18株流行株的氨基酸序列与国内已报道的代表株相比发生不同程度的变异,GP5抗原表位上存在着差异。研究结果揭示了广东地区PRRSV有新型强毒株、重组毒株以及疫苗返强毒株的流行,提示养殖者谨慎、合理使用疫苗,防止疫苗毒株返强和毒株重组,为该地区防控PRRS提供参考。  相似文献   

14.
Twenty-eight PRRS viruses (PRRSVs) isolated from various pig farms in Korea between 2002 and 2003 were sequenced for open-reading frame (ORF) 5 and/or full-length genome and compared with numerous PRRSVs reported from North America, Europe and Asia. All Korean isolates examined were genetically of the North American genotype. The ORF5 sequence of one isolate was identical to Ingelvac PRRS MLV vaccine virus. ORF5 nucleotide sequence divergence of the remaining 27 Korean PRRSVs from VR-2332, the prototype of the North American PRRSV and parental strain of the MLV vaccine virus, ranged from 1.3% to 12.9%, which corresponded to 2.0% to 14.9% divergence at the amino acid level, raising a concern on the efficacy of the MLV vaccine. Phylogenetic analyses of ORF5 and/or full-length sequences revealed that the Korean PRRSVs formed a clade distinct from PRRSVs reported from other Asian countries (China, Taiwan, Japan, and Thailand). Our study demonstrated that PRRSVs of the North American genotype were introduced to the Korean swine population some time ago and have evolved independently from PRRSV in other Asian countries, suggesting that geographic separation might influence the molecular evolution of PRRSV. This should be taken into consideration when a national PRRS prevention and control policy for international trade is established.  相似文献   

15.
为了解我国华北地区类NADC30流行猪繁殖与呼吸综合征病毒(PRRSV)及遗传变异情况,本研究自2016~2017年采集华北四省市(北京、天津、山东及河北)部分猪场疑似PRRSV样品239份进行RT-PCR检测,对所有阳性样品的ORF5基因测序分析及部分阳性样品病毒分离,并选择1株基因缺失病毒TJjh1602株进行全基因的序列扩增及分析.结果显示:PRRSV检测总阳性率44.35%(106/239),遗传进化显示52.83%(56/106)的流行毒株与类NADC30相近且位于系谱1(lineage 1),其中32.14%(18/56)的类NADC30流行毒株具有相同特征性的氨基酸位点缺失;TJjh1602株全基因长度为15018 nt,与NADC30同源性为95.2%,除具有上述特征性氨基酸位点缺失外,无其他插入或缺失.研究结果推测PRRSV类NADC30毒株在我国华北地区广泛流行,同时已遗传演化成一类具有ORF5缺失分子标签的新型类NADC30毒株,提示需进一步加强对PRRSV新型缺失毒株的流行病学调查及相关致病力研究.  相似文献   

16.
Various vaccine adjuvant candidates were assessed with the modified-live porcine reproductive and respiratory syndrome virus (MLV PRRSV) (Ingelvac PRRS MLV) vaccine. Their influence on humoral-mediated immune (HMI) and cell-mediated immune (CMI) responses as well as protection from virulent PRRSV challenge (MN-184) was evaluated. Ninety seronegative pigs were randomly divided into nine groups of 10 pigs. One group received MLV vaccine alone. Five groups received MLV vaccine with either bacterial endotoxin-derived adjuvant (ET), mixed open reading frame 5 (ORF5) peptides derived from various PRRSV isolates, porcine interferon alpha (IFNalpha), polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose (poly-ICLC), or porcine interleukin-12 (IL-12). One group did not receive MLV vaccine but was immunized with ORF5 peptides conjugated with cholera toxin (ORF5 peptide/CT). Two groups served as challenged and unchallenged non-vaccinated controls. Four-color flow cytometry was utilized to simultaneously identify three major porcine T-cell surface markers (CD4, CD8, and gammadelta TCR) and detect activation marker CD25 (alpha chain of IL-2 receptor) or intracellular IFNgamma. The MLV PRRSV vaccine alone successfully primed CD4(-)CD8(+)gammadelta- T-cells as demonstrated by a significant increase in %IFNgamma+ cells when live PRRSV was used as a recall antigen. Booster immunizations of mixed ORF5 peptides and co-administration of IL-12 with MLV PRRSV vaccine significantly enhanced IFNgamma expression by some T-cell subsets (CD4(-)CD8(+)gammadelta+ and CD4(-)CD8(-)gammadelta+ for mixed ORF5 peptides and CD4(+)CD8(+)gammadelta- and CD4(-)CD8(+)gammadelta+ for IL-12). All groups receiving MLV-vaccine with or without adjuvants had reduced lung lesions after challenge. The group immunized with only ORF5 peptide/CT did not have significant T-cell recall responses and was not protected from challenge. Expression of IFNgamma by several T-cell subsets correlated with reduced lung lesions and viremia, whereas expression of CD25 did not. Expression of surface CD25 did not correlate with IFNgamma production. PRRSV ELISA s/p ratio prior to challenge also correlated with reduced lung lesions and viremia. In conclusion, booster immunizations of the mixed ORF5 peptides and co-administration of IL-12 effectively enhanced the CMI response to MLV vaccine. However, neither adjuvant significantly contributed to reducing clinical effects when compared to MLV alone.  相似文献   

17.
为了解广西地区猪繁殖与呼吸综合征病毒(PRRSV)流行毒株的遗传进化情况,对2014年-2016年来自广西各地的部分PRRSV阳性病料进行Nsp2和ORF5基因的扩增和测序分析.结果获得34个Nsp2基因序列和45个ORF5基因序列,均属于美洲型毒株.Nsp2基因间核苷酸序列的同源性为91.8％~100％,与PRRSV美洲型毒株VR-2332、CH-1a、JXA1及NADC30株核苷酸序列的同源性分别为81.3％~84.3％、88.9％~92.1％、94.3％~99.3％和73.5％~75.1％,而与PRRSV欧洲型毒株LV株核苷酸序列的同源性为51.5％~53.2％.ORF5基因间核苷酸序列的同源性为82.8％~100％,与PRRSV美洲型毒株VR-2332、CH-1a、JXA1及NADC30株核苷酸序列的同源性分别为83.7％~99.5％、85％~95％、83.8％~99.7％和83.2％~86.4％,而与PRRSV欧洲型毒株LV株核苷酸序列的同源性为62.4％~64.5％.基于Nsp2和ORF5基因推导的氨基酸序列绘制的遗传进化树中,广西地区的毒株主要分布在以JXA1为代表的Ⅳ亚群.表明当前广西PRRSV流行毒株以JXA1株为代表的高致病性美洲型毒株为主,各毒株Nsp2和ORF5基因序列存在一定的差异,尚未发现欧洲型毒株和美洲型NADC30类毒株.  相似文献   

18.
为研究江西地区猪繁殖与呼吸综合征病毒(PRRSV) ORF5基因的变异情况及NSP2基因的结构特征,采用RT-PCR方法扩增了12份江西地区猪场疑似患PRRS的猪肺脏样品中的ORF5全序列和NSP2部分序列,应用DNAStar和Mega 6.0等软件对所得序列进行同源性比对及遗传变异分析。12株PRRSV ORF5核苷酸同源性为83.7%~99.8%,氨基酸同源性为82.1%~99.5%;与参考毒株JXA1、VR-2332和LV的核苷酸同源性分别为84.9%~99.7%、85.2%~91.0%和62.4%~64.8%。对阳性病料进行了NSP2基因部分序列的扩增,测序结果显示12株PRRSV均属于美洲型毒株,12株PRRSV的NSP2部分序列均存在30个氨基酸的不连续缺失,与高致病性PRRSV有相同的缺失特征。12株PRRSV的ORF5遗传进化树分析显示,10株与高致病性PRRSV处在同一进化分支,进一步说明高致病性PRRSV已成为江西地区的优势流行毒株。  相似文献   

19.
The porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important viral pathogens in the swine industry. Despite great efforts of pig holders, veterinarians, researchers and vaccine developers, the virus still causes major production losses. It is clear that efficient and correct monitoring and rational development of vaccines are crucial in the combat against this pathogen. PRRSV-specific monoclonal antibodies (mAbs) are essential tools for both diagnostic and research purposes. This study describes the production of PRRSV GP3-, GP5- and N-specific hybridomas and an extensive characterization of the mAbs. The N-specific mAbs generated in this study appear to be useful tools for diagnostics, as they were found to react with genetically very different PRRSV isolates and may serve to discriminate between European and American type PRRSV isolates. These mAbs also allowed detection of the PRRSV N protein in both formalin-fixed, paraffin-embedded tissue sections and frozen tissue sections of PRRSV-infected lungs, further illustrating their diagnostic value. Different neutralization assays pointed out that none of the GP3- and GP5-specific mAbs tested shows virus-neutralizing capacity. This is noteworthy, as these mAbs recognize epitopes in the predicted ectodomains of their target protein and since the GP5-specific antibodies specifically react with the antigenic region that corresponds to the "major neutralizing epitope" suggested for American type PRRSV. The current findings argue against an important role of the identified antigenic regions in direct antibody-mediated neutralization of European type PRRSV in vivo. However, it is also clear that findings concerning a specific PRRSV epitope cannot always be generalized, as the antigenic determinants and their biological properties may differ radically between different virus isolates.  相似文献   

20.
为了解山东省PRRSV流行毒株的遗传变异情况和分子流行病学背景,对2007~2009年分离到的14株山东省内的PRRSV流行毒株进行了Nsp2和ORF5基因序列的测定和分析。结果显示,与参考毒株JXA1相比,14株PRRSV Nsp2与ORF5基因的核苷酸同源性分别达到96.1%~99.8%和98.0%~99.8%,氨基酸序列同源性分别达到92.9%~100%和97.5%~99.5%。序列分析结果表明,14株毒株在Nsp2蛋白内部均存在编码30个氨基酸的碱基对的不连续缺失;ORF5基因编码的GP5蛋白不存在缺失,但存在点突变。遗传进化分析表明,07年分离毒株JQ与参考毒株JXA1亲缘关系很近;09年分离的12株PRRSV,2株仍与国内2006~2007年间的分离株在同一分支,9株已经处在不同分支,1株单独处在一个分支。2007~2009年山东地区流行的PRRSV分离株具有年度特征,无明显的地域特征。  相似文献   

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