猪瘟疫苗在猪圆环病毒2型阳性猪场的免疫效果观察

为了研究猪圆环病毒2型(PCV-2)感染对猪瘟疫苗免疫效力的影响,对PCR证实为PCV-2阳性的试验猪进行猪瘟疫苗的免疫,分别在免疫后第1、3、7、14、21、28和63天对试验猪进行猪瘟病毒(CSFV)和PCV-2的抗体检测。检测结果表明PCV-2阳性猪在猪瘟疫苗免疫后均未能产生有效的CSFV抗体,从免疫猪的血液和内脏组织中也未能检测到CSFV核酸。虽然只能从1头PCV-2阳性猪的血清中检测到PCV-2抗体,但是却能从全部实验猪的淋巴结中检测到PCV-2的核酸。试验猪的病理组织学观察和白细胞计数也表明PCV-2阳性猪的淋巴结呈典型的PCV-2感染的病理变化,且白细胞数量显著低于健康猪。表明PCV-2的感染会对猪的免疫系统造成损害从而抑制猪瘟疫苗的免疫效果。     

用PCR法检测猪繁殖-呼吸综合征病毒和猪圆环病毒混合感染病例研究

根据已发表的猪繁殖-呼吸综合征病毒(PRRSV)、猪圆环病毒2型(PCV-2)的核苷酸序列设计特异性引物，应用PCR方法对从福清市某养猪场病猪采集的淋巴结、肺、脾等器官组织病料进行检测，发现该猪场病猪病料的检测结果PRRSV和PCV-2同时为阳性，从而证实了PRRSV和PCV-2在该病猪体内混合感染。     

猪皮炎肾病综合征组织病理学和PCR诊断

应用病理学和PCR方法,对浙江某猪场送检的疑似猪皮炎肾病综合征（PDNS）病猪进行诊断。结果发现肾脏呈现纤维蛋白性肾小球肾炎变化,真皮及皮下血管表现为坏死性脉管炎,淋巴组织中大量淋巴细胞缺失、多核巨细胞浸润,PCR扩增产物显示猪圆环病毒2型（PCV-2）阳性。结果表明,该猪场感染了PCV-2,并表现为PDNS的病理特征。     

某猪场“僵猪”致病原因分析

为分析某猪场出现"僵猪"的可能原因,对该猪场的11头"僵猪"采集血液样品,用RT-PCR方法检测猪瘟病毒(CSFV)和猪繁殖与呼吸综合征病毒(PRRSV),用PCR方法检测猪伪狂犬病毒(PRV)和猪圆环病毒2型(PCV-2)。结果11份样品的CSFV、PRRSV及PRV检测均为阴性,PCV-2经套式PCR检测均为阳性。对11份样品分离血清,应用酶联免疫吸附试验(ELISA)检测PCV-2血清抗体,结果均为阳性。随后又对与11头"僵猪"同舍的部分健康猪进行了上述4种病毒的RT-PCR及PCR检测,结果均为阴性。由此推测PCV-2极有可能是该猪场形成"僵猪"的主要因素之一。     

珠三角地区猪圆环病毒2型的分离鉴定及序列分析

为了解珠三角地区猪群中猪圆环病毒2型(PCV-2)的流行变异情况,从2008年-2010年珠三角地区疑似PMWS病死猪组织中分离获得PCV-2流行毒株,用间接免疫荧光方法进行检测和用PCR方法对这些毒株进行全基因扩增及测序分析.结果显示,在接毒细胞内观察到了特异性免疫荧光,8株PCV-2分离株与GenBank中的其他P...     

免疫组化法检测猪圆环病毒2型在人工感染猪体内的分布

将猪圆环病毒2型（PCV2）BF株经滴鼻接种28日龄健康普通仔猪,于接种后不同时间剖杀,采集相关的器官组织制备组织切片,使用免疫组化方法检测病毒在猪体内的分布。结果显示,淋巴结、脾脏、扁桃体等淋巴组织均出现阳性信号,心、肝、肺、肾、胃、十二指肠、大脑及小脑同样存在阳性细胞,其他组织呈阴性反应。阳性信号主要位于感染细胞的胞质中,偶尔出现在细胞核内。结果表明,PCV2确已造成猪体组织感染。     

猪PCV-2和附红细胞体混合感染的实验报告

采取成都某猪场7头病猪料，经PCR检测后，有4头呈PCV-2阳性。以PCV-2阳性病料接种PK-15猪肾传代细胞，经分离和鉴定，获得PCV-2成都株。该猪场同时流行猪附红细胞体病，存在PCV-2和E．suis的混合感染。     

猪圆环病毒2型PCR检测方法的建立及应用

为了研究猪圆环病毒2型(PCV-2)的分子生物学检测方法,试验根据GenBank中PCV-2的序列设计1对特异性引物,用PCR方法扩增猪PCV-2基因保守区序列,并对PCR扩增程序进行优化,对PCR检测方法的特异性、敏感性、重复性进行研究;并用该方法对来自红河州规模化猪场的178份临床发病猪的肺脏和淋巴结样品进行检测。结果表明:该法具有快速、敏感、特异等优点,可用于PCV-2的检测和流行病学调查等;178份临床病料中有83份阳性样品,阳性率为46.6%。     

屠宰生猪PCV-2感染的检测与基因型分析

为了解屠宰生猪中猪圆环病毒2型(PCV-2)的带毒状况及PCV-2的主要基因型,在分析PCV-2分离株基因序列的基础上分别设计了检测PCV-2、PCV2-A和PCV2-B的引物,建立了各自的PCR检测方法。结果表明,建立的PCV-2、PCV2-A、PCV2-B的PCR检测方法,特异性较好,可用于临床病料的检测;通过对临床采集的49分生猪血样的检测发现,PCV-2的阳性率为24.49%,均属于PCV2-B。检测结果表明,当地检测猪群中感染的PCV-2主要为PCV2-B毒株,在该病的防控方面应引起注意。     

猪圆环病毒2型与链球菌7型协同感染研究

2016年10月,在山东省发现猪圆环病毒2型(PCV-2)和链球菌7型协同感染病例。猪场小猪40日龄发病,持续至100日龄时死亡率高达30%,病猪表现为精神沉郁、发热、四肢无力和呼吸困难,最后衰竭死亡。采用血液学检测,病理组织学观察,细菌、病毒分离鉴定和动物回归试验验证。结果表明,血液中大量红细胞变形,淋巴细胞、中性粒细胞数量增多;分离的细菌为短链状排列的革兰阳性球菌,直径1μm~2μm;16SrRNA PCR测序结果显示为链球菌7型;病毒PCR结果显示为PCV2阳性,猪瘟病毒、猪伪狂犬病病毒、猪繁殖与呼吸综合征病毒、猪细小病毒均为阴性;遗传进化分析表明PCV-2检测株与PCV-Y16同源性最高,为99.7%。随后,PK-15细胞连续传代显示PCV-2在PK-15细胞中增殖。动物回归试验中,临床数据统计结果、剖检病变以及组织病理学观察证实两种病原具有协同致病性。根据猪群临床症状、剖检病变、组织学病变、病原检测结果以及动物回归试验,最终确诊该猪群发生PCV-2与链球菌7型的混合感染,并呈现致病上的协同作用。     

华南地区猪圆环病毒和猪繁殖与呼吸综合征病毒检测分析

为了解华南地区猪圆环病毒及猪繁殖与呼吸综合征病毒的最新流行情况,采集了华南地区11个规模猪场各饲养阶段猪血清807份,用套式PCR(nPCR)检测猪圆环病毒1型(PCV-1)和猪圆环病毒2型(PCV-2);采集了若干猪场2010年1月至2011年8月期间有咳嗽、喘气、消瘦及疑似PDNS等临床症状的猪血清312份,以及无临床症状猪血清104份,以nPCR检测PCV-2,以一步法反转录PCR(RT-PCR)检测猪繁殖与呼吸综合征病毒。结果发现,所调查的11个规模猪场中只有5个检出PCV-1,所有猪场均检出PCV-2。PCV-2阳性率为30.61%,而PCV-1阳性率仅为4.21%;经产母猪和7周龄以上保育猪PCV阳性率最高;有临床症状的猪血清PCV-2阳性率为58.65%,PRRSV阳性率为37.82%,PCV-2阳性猪群中有39.89%的猪同时感染PRRSV;有症状猪群7月～9月的PCV-2感染率最高,而1月～3月最低;无临床症状猪血清PCV-2阳性率为27.9%,PRRSV阳性率为0.96%,PCV-2与PRRSV无混合感染。证明PCV尤其是PCV-2在华南地区仍广泛传播并流行,而且PCV-2与PRRSV混合感染致病情况较多。PCV-2的感染率与季节有一定的相关性,种猪带毒情况严重。     

The emergence of a new strain of porcine circovirus-2 in Ontario and Quebec swine and its association with severe porcine circovirus associated disease — 2004–2006

In the late fall of 2004 more severe lesions of porcine circovirus-2 associated disease (PCVAD) than usual occurred during an outbreak of porcine circovirus-2 (PCV-2) infection in Ontario nursery and grower/finisher pigs. The lesions were of unprecedented severity and included diffuse bronchointerstitial pneumonia, granulomatous enteritis, vasculitis, interstitial nephritis, and new lesions of splenic infarction. Some affected herds had up to 50% mortality. The outbreak correlated with the sudden emergence of a variant PCV-2, with PCR restriction fragment length polymorphism (RFLP) type 321. Phylogenetic comparison of ORF2 sequences and full genome sequences showed the new variant to be different from the previously dominant RFLP type 422 viruses, and similar to viruses that had occurred in France and other European and Asian countries. A subsequent retrospective study showed a statistically significant increase in the frequency of histological lesions in lymph node, spleen, lung, small intestine, colon and kidney, for pigs spontaneously infected with RFLP type 321, compared with the older RFLP type 422 strain. Viral burden, based on IHC staining in lymph node, also showed a statistically significant increase in pigs infected with the newer variant RFLP type 321, compared with the older RFLP type 422 strain. This enhanced virulence in pigs infected with PCV-2 RFLP type 321 strain may be related to the genetic differences in this new strain of PCV-2. This virus is now the dominant strain of PCV-2 virus found in Ontario and Quebec swine.     

Seroprevalence of economically important viral pathogens in swine populations of Trinidad and Tobago,West Indies

The objective of this study was to evaluate the seroprevalence and identify the strains of swine influenza virus (SwIV), as well as the seroprevalence of porcine parvovirus (PPV), transmissible gastroenteritis virus (TGEV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine respiratory coronavirus (PRCV), porcine circovirus type 2 (PCV-2), and classical swine fever virus (CSFV) in pigs in Trinidad and Tobago (T&T). Blood samples (309) were randomly collected from pigs at farms throughout T&T. Serum samples were tested for the presence of antibodies to the aforementioned viruses using commercial ELISA kits, and the circulating strains of SwIV were identified by the hemagglutination inhibition test (HIT). Antibodies against SwIV were detected in 114 out of the 309 samples (37%). Out of a total of 26 farms, 14 tested positive for SwIV antibodies. HI testing revealed high titers against the A/sw/Minnesota/593/99 H3N2 strain and the pH1N1 2009 pandemic strain. Antibodies against PPV were detected in 87 out of the 309 samples (28%), with 11 out of 26 farms testing positive for PPV antibodies. Antibodies against PCV-2 were detected in 205 out of the 309 samples tested (66%), with 25 out of the 26 farms testing positive for PCV-2 antibodies. No antibodies were detected in any of the tested pigs to PRRSV, TGEV, PRCV, or CSFV.     

ELISA对猪场PCV-2血清抗体的检测

应用酶联免疫吸附试验(ELISA)对三个猪场的89份血清样本进行猪圆环病毒Ⅱ型(PCV-2)血清抗体的检测，本次检测PCV-2的总阳性率为2．24％。在甲猪场的48份血清中检出猪PCV-2阳性2份，4份可疑，阳性率为4.17％；而乙、丙两猪场的血清样本均呈阴性。结果表明：甲猪场可能有猪PCV-2的存在，而乙、丙两猪场尚处于未被猪圆环病毒污染的状态。     

FRRSV和PCV-2双重PCR检测方法的建立及应用

根据猪繁殖与呼吸综合征病毒(PRRSV)美洲型标准株(ATCCVR-2332)的ORF7保守序列和猪圆环病毒2型(PCV-2)(AF381175)的ORF2基因保守序列,设计合成了两对特异性引物。用这两对引物,通过优化的PCR条件,对PRRSV阳性毒株反转录后的cDNA模板和PCV-2毒株的DNA模板进行双重PCR扩增,同时得到两条与试验设计相符的432bp(PRRSV)和630bp(PCV-2)特异性条带,建立了同时检测PRRSV和PCV-2的双重PCR方法。并用此方法对在安徽省不同地区所采集的72头份病猪的淋巴结、肺、肝、脾、肾等组织进行检测,证明建立的PCR方法可用于临床诊断。     

上海及周边地区猪圆环病毒2型基因型分析

采集上海及周边地区猪内脏样本,进行猪圆环病毒2型（Porcine circovirus type 2,PCV-2）病原学检测,并对阳性样本的ORF2序列进行分析和比对。结果显示,发病猪群PCV-2阳性率为39.06%（25/64）,健康猪群阳性率为13.51%（5/37）,PCV-2总阳性率为29.70%（30/101）。30份阳性样本中PCV-2a亚型为2株,检出率为1.98%（2/101）,其余28株均为PCV-2b亚型,检出率为27.72%（28/101）。PCV-2的ORF2序列与已登录的ORF2序列的同源性在90.7%~100%。2株PCV-2a株相互间的同源性为99.6%;28株PCV-2b株的同源性在94.4%~100%,PCV-2b株中只有4株与已登录株DQ141322、AY321984和AY484413株同源性关系最近,处于同一分支中,而另外24株与Q151643中国株同源性关系最近且处于同一分支中。研究结果表明上海及周边地区PCV-2感染比较普遍,发病猪场的感染率远高于健康猪场,且感染率比往年有升高,PCV-2在猪场疫病的爆发和传染中起着重要的协同作用;在PCV-2的感染病例中,PCV-2b亚型为感染的优势毒株;绝大多数PCV-2b ORF2片段的同源性与已登录的一株中国株同源性关系密切,在基因进化树上处于同一分支,但是否可以推断其为PCV-2的另一个亚型有待进一步考证。     

猪圆环病毒2型的分离鉴定及全基因组克隆和序列分析

通过PCR方法对采自四川省某规模化猪场一批疑似断奶仔猪多系统衰弱综合征病例的肺脏、淋巴结进行PCV-2的抗原检测,并将检测结果为阳性的对应组织研磨、过滤除菌后接种无PCV-1污染的PK-15细胞,盲传15代后,IFA方法检测出有明显的特异性荧光,将该毒株命名为PCV-2-SC株,并对PCV-2-SC病毒基因组全长进行扩增及克隆、测序与比对分析。测序结果显示该病毒基因组全长1 767bp,分离株与国内外参考毒株核苷酸序列相似性在95.2%～99.5%之间,进化树分析表明,PCV-2分离毒株在进化上存在地域相关性。PCV-2四川株的分离鉴定为其诊断试剂的研制及检测方法的建立奠定了基础。     

Investigation of the prevalence of swine torque teno virus in Austria

In the present retrospective study, serum samples from a total of 253 pigs of different age groups from 83 farms collected in the year 2008 were included.The sera were analysed for the presence of torque teno virus (TTV) genogroups 1 and 2. Furthermore, the correlation between TTV and PCV-2 was investigated. 62.1% of the pigs were positive for TTV1 and/or TTV2 by PCR. 21.7% of the samples were positive for TTV1 and TTV2, 16.2% only for TTV1 and 23.3% only for TTV2. In 80.7% of the investigated farms at least one animal was TTV positive. In the growing and fattening period significantly more pigs were positive for TTV than in other age classes. A positive association was found between TTV1 and IgM against PCV-2, between TTV2 and PCV-2 results by in situ hybridisation (ISH) as well as TTV1 and TTV2 and PCV-2 results by qPCR. A significant correlation could also be seen between the diagnosis,porcine respiratory disease complex (PRDC)" and the detection of TTV, whereas there was none to the diagnosis "porcine dermatitis and nephropathy syndrome (PDNS)". In the present study, TTV was detected in Austria for the first time.