某猪场猪2型圆环病毒感染的诊断

猪2型圆环病毒(PCV2)是引起断奶仔猪多系统衰竭综合征(PMWS)的主要病原,此外,PCV2还可能与猪皮炎肾病综合征、猪呼吸系统综合征、仔猪先天性震颤等疾病有关.PMWS临床症状主要表现为进行性消瘦,生长发育受阻,皮肤苍白或有黄疸,体表淋巴结肿大,腹泻,贫血和呼吸道症状等.     

The effect on reproductive performance of porcine parvovirus infection in a susceptible pig herd

An acute episode of reproductive failure occurred following natural introduction of porcine parvovirus to a susceptible herd of 48 breeding sows. Serological data gave a close estimate of the time that infection spread through the herd, and enabled a correct forecast of the reproductive failure that followed. Severe fetal mummification was seen over a three-week period. Epidemiological data is presented strongly linking in utero parvovirus infection with the mummification that occurred, and the significance of this data is discussed in connection with the present knowledge of transplacental porcine parvovirus infection.     

猪圆环病毒疫苗临床免疫效果观察

猪圆环病毒2型(PCV2)是危害世界养猪业的一个重要病原,造成巨大经济损失。本试验选用PCV2 SH毒株水包油包水乳剂及其水佐剂灭活疫苗、进口的Ingelvac~?CircoFLEX~(TM)基因工程亚单位疫苗和国产的大肠杆菌表达的重组Cap亚单位疫苗,在确诊PCV2感染的某规模化猪场开展仔猪免疫试验。结果显示:两种PCV2 SH株灭活疫苗均能明显降低发病率和死亡率,降低病毒血症,提高日增重,其免疫效果与CircoFLEX疫苗相当,优于大肠杆菌表达的重组Cap亚单位疫苗,值得推广应用。     

Reproductive losses associated with porcine circovirus type 2 in a Japanese herd of seronegative sows

From April to July 2009, there was a high rate of reproductive losses in a 30-sow, farrow-to-finish swine herd in Yamagata Prefecture, Japan. Histopathological examinations of heart tissue from stillborn and preweaning piglets showed nonsuppurative, necrotizing lesions. Immunohistochemical staining and polymerase chain reaction analysis of myocardial lesions revealed the presence of porcine circovirus type 2 (PCV2) antigens and DNA in these tissues. Indirect immunofluorescence also showed that the PCV2 antibody positive rate in the sows was higher in May 2009 than in December 2008. The results of this study suggest that PCV2 spread to this farm and caused a high rate of reproductive losses.     

辽宁省某规模化猪场圆环病毒Ⅱ型的PCR检测

猪圆环病毒(Porcine circovirus,PCV)是迄今为止发现的最小的一种脊椎动物病毒.PCV分为无致病性(或PK15源性)的猪圆环病毒Ⅰ型(PCV-1)和有致病性(PMWS源性)的猪圆环病毒Ⅱ型(PCV-2)两个基因型[1-2].     

猪圆环病毒疫苗在规模化猪场的使用效果研究

为了比较分析湖北省某规模化猪场猪圆环病毒亚单位疫苗和全病毒灭活疫苗的使用效果,选择21日龄健康仔猪1 000头,随机分为3组,每组330~336头,分别免疫亚单位疫苗(A组)、灭活疫苗(B组)和生理盐水(C组);免疫后30、60和90 d,通过检测猪只的生产性能、抗体水平和血清中病毒含量来比较2种疫苗的免疫效果。结果显示:相比较于生理盐水组,2种疫苗免疫商品猪后,均能显著提高日增重(P0.05),降低死淘率和肉料比,提高血清抗体水平和减少排毒。而且,亚单位疫苗的免疫效果优于目前的常规灭活疫苗,值得推广应用。     

规模化猪场猪圆环病毒2型感染的实验室诊断

为了确诊贵州省某规模化猪场保育仔猪异常死亡原因,从怀孕母猪、产房母猪、后备母猪、种公猪、哺乳仔猪、保育仔猪6个猪群采集90份血清样本采用ELISA方法分别进行血清抗体检测,并对采集的90份血清样本和1份病死猪淋巴结组织采用荧光PCR方法进行病原学检测。结果:6个猪群综合的猪瘟病毒、猪蓝耳病病毒、伪狂犬病病毒g B蛋白、伪狂犬病病毒g E蛋白血清抗体阳性率分别为87.78%、70.00%、88.89%、4.44%;猪瘟病毒、猪蓝耳病病毒、伪狂犬病病毒病原核酸检测显示阴性,猪圆环病毒2型病原核酸检测淋巴结组织样本显示阳性。试验结果表明,引起该猪场保育仔猪死亡的原因为猪圆环病毒2型感染。同时,怀孕母猪群出现了伪狂犬病病毒g E蛋白抗体阳性,提示怀孕母猪群可能存在猪伪狂犬病野毒感染。     

Genetic characterisation of Australian strains of porcine circovirus types 1 and 2

OBJECTIVE: As post-weaning multi-systemic wasting syndrome (PMWS) has not been identified within Australia, to determine if the absence of disease was associated with genetic differences between the strains of porcine circovirus (PCV) present in Australia and those from countries in association with PMWS. DESIGN: Pig tissues were obtained from weaned pigs found dead or presenting with clinical signs of illthrift and also from neonatal pigs with congenital tremors and used as a source of virus DNA for sequence analysis. PROCEDURE: DNA was extracted from the tissues and PCV detected by polymerase chain reaction (PCR). PCR with PCV type-specific primers was used to amplify the entire genome from selected tissues. The genomes of three strains of PCV1 and seven strains of PCV2 from three Australian states were sequenced and subjected to phylogenetic analysis using standard procedures. RESULTS: The three Australian PCV1 strains had 98 to 99% nucleotide identity to strains in other countries and the seven Australian PCV2 strains had 94 to 99% identity to PCV2 strains in other countries where PMWS has occurred. Six of the seven Australian PCV2 strains were genetically similar to each other, while the seventh was more distantly related. There were no consistent differences in the predicted amino acid sequence of the Australian strains of PCV2 and strains associated with PMWS in other countries. CONCLUSION: There were no consistent differences between Australian strains of PCV and those that have been associated with PMWS in other countries and it appears likely that other factors are responsible for the absence of PMWS in Australia.     

猪圆环病毒的研究进展

圆环病毒能引起猪的传染性、先天性颤抖和断奶仔猪多系统衰弱综合症,现已成为严重影响养猪业发展的病毒之一.作者从猪的圆环病毒所引起疾病的流行现状、致病机理、病理变化、临床诊断、预防等方面进行了论述.     

猪瘟病毒和猪圆环病毒混合感染病例的诊治

本文对2017年5月山东省新泰市某养殖场的一头病死猪病例进行了诊断,经临床症状检查、病理剖检、RT-PCR检测、PCR检测等,最终判定该病例为猪瘟病毒和圆环病毒混感。     

猪圆环病毒2型检测与免疫技术研究进展

对年近来国内外对猪圆环病毒2型(PCV2)的检测技术进展和疫苗研究进展作了简要回顾。PCV2实验室检验技术有间接免疫荧光(IFA)、间接酶联免疫吸附试验(ELISA)、免疫过氧化物酶单层细胞试验(IPMA)、单克隆抗体以及多种聚合酶链式反应(PCR)技术等。在疫苗研究方面,国外已研发多种PCV2灭活疫苗,国内亦有人正在研发PCV2灭活苗(SH株)。在PCV2基因工程疫苗研究方面主要有重组活载体疫苗和核酸疫苗两类。     

某规模化猪场猪2型圆环病毒病流行病学调查

为了弄清猪2型圆环病毒感染在该猪场的感染状况、流行特点及优势基因型等情况。采用ELISA检测技术和PCR技术,对新疆某规模化猪场的不同生产阶段猪群进行猪2型圆环病毒(PCV2)抗体检测和基因型检测。结果猪圆环病毒病(PCVD)在该猪场猪群中的平均抗体阳性率为72.41%,不同生长阶段的猪群感染情况分别为哺乳仔猪69.74%、断奶仔猪62.75%、育肥猪77.88%、母猪81.67%以及种公猪83.33%;对采集的11份抗体阳性的断奶猪只的脏器病料PCR检测,其中5份为PCR阳性(45.45%),经克隆测序分析发现,该猪场5株PCV2毒株序列之间的相似性在99.3%⁹9.9%之间,且均属于PCV2b这一亚型。结果表明,该猪场的PCV2感染流行已非常严重,整体流行特征表现为猪只日龄越大,感染情况越严重,且流行的优势基因型为PCV2b亚型,应该引起养殖户的高度重视,需要立即采取针对有效的防治净化措施。     

Dynamics of porcine circovirus type 2 infection in a herd of pigs with postweaning multisystemic wasting syndrome

OBJECTIVE: To determine the pattern of infection for porcine circovirus type 2 (PCV2) in a herd of pigs with postweaning multisystemic wasting syndrome (PMWS). ANIMALS: 29 sows and 250 pigs. PROCEDURE: Blood samples were collected from all 3-, 7-, and 12-week old pigs and 59 pigs at 28 weeks of age. Pigs that died during the study were necropsied. Porcine parvovirus and PCV2 antibodies were assayed. A polymerase chain reaction (PCR) was used to detect PCV2 genome in serum of selected pigs. RESULTS: The PMWS started when pigs were 8 weeks old, with a prevalence of 30% in 8- to 10-week-old pigs. Eighty-three pigs died during the period between 3 and 12 weeks of age. Microscopic lesions consistent with PMWS were observed, and PCV2 nucleic acid was detected (50 of 68 pigs). Antibodies to PCV2 decreased from 3 to 7 weeks of age, increased at 12 weeks of age, and were maintained until 28 weeks of age. One sow had a positive result for PCR of serum. Nine, 37 and 8 pigs had PCV2 genome in serum obtained at 7, 12, and 28 weeks of age, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Infection with PCV2 coincided with severe clinical signs; however, infected 28-week-old pigs did not have evidence of disease. Immunity declined over time in young pigs. A long duration of PCV2 viremia was apparent in a high percentage of infected pigs, which may affect transmission and persistence of the virus in a herd.     

PCR detection and characterization of type-2 porcine circovirus.

A polymerase chain reaction (PCR) assay was developed for detecting porcine circovirus (PCV). The assay readily detected type-2 PCV (PCV-2) and type-1 PCV (PCV-1). The PCR primers were designed based on DNA sequences conserved in all reported PCV genomes. Type 1 PCV and type 2 PCV both produced 438 bp amplification products, which were easily identified and differentiated from one another by restriction fragment length polymorphism (RFLP) analysis. Porcine circovirus was detected in 55% (931/1693) of randomly tested pigs with various clinical signs and lesions, most of which were difficult to differentiate from those associated with porcine reproductive and respiratory syndrome (PRRS). The PCR products from all positive clinical samples were identified by RFLP to be only PCV-2; DNA tested by PCR was extracted directly from one or more of lung, mesenteric or mediastinal lymph nodes, and tonsil. Type 2 PCV was also detected in 6% (2/34) of DNA extracted directly from semen of randomly chosen healthy boars. Positive PCR reactions from 554 diseased pigs were characterized by RFLP and categorized into 5 different profiles (A-E), of which 82.8% were PCV-2A (456/554), 3.0% were PCV-2B (17/554), 9.9% were PCV-2C (55/554), 1.1% were PCV-2D (6/554), and 3.2% were PCV-2E (18/554). The complete genomic nucleotide sequences of PCV-2A, B, C, D, and E were determined and found to have at least 95% homology compared with one another and with all other PCV-2 found in the GenBank database. All PCV-2 had less than 76% homology with PCV-1. This PCR assay will hopefully be useful to veterinary diagnostic laboratories for routine testing and surveillance of infection with PCV-2. The RFLP profiling system might be useful for preliminary characterization and identification of PCV isolates and might also benefit studies on the molecular epidemiology of PCV.     

福建省部分规模猪场猪圆环病毒病疫苗免疫效果评价与分析

为了解免疫不同圆环病毒病疫苗的抗体水平,给养殖户提供合适的免疫依据,对福建省不同地区8个猪场在使用不同猪圆环病毒病疫苗和免疫程序后猪群的抗体水平进行检测。结果显示:免疫场和未免疫场各阶段种猪群的猪圆环病毒病抗体阳性率皆为100%,差异不显著(P>0.05);但各阶段种猪群的S/P平均值,免疫场较未免疫场更高;同时通过比较变异系数发现,未免疫场种猪的抗体水平更活跃;14日龄免疫亚单位疫苗后抗体水平较高且维持时间较长,而免疫全病毒灭活苗后抗体水平仍持续下降。综上,种猪群免疫圆环病毒病疫苗是必要的,亚单位疫苗比全病毒灭活苗的免疫效果好。     

Detection of porcine circovirus from lesions of a pig with wasting disease in Japan

A wasting disease characterized by progressive weight loss and dyspnea has been observed in weaning pigs on a farm in Yamagata Prefecture in 1998. Histopathologic findings in an affected pig were bronchointerstitial pneumonia and intracytoplasmic clusters of basophilic inclusions in macrophages of lymph nodes, which were similar to those in pigs with postweaning multisystemic wasting syndrome (PMWS) recently reported in North America and Europe. Porcine circovirus (PCV)-like particles were observed in bronchial lymph node of the pig by electron microscopy, and PCV antigens were detected in the lesions by immunohistochemical staining. PCV DNA was also detected in the lung and tonsil by PCR, and restriction fragment length polymorphism analysis of the PCR products with HinfI showed the same type of the PCV associated with PMWS (pmws PCV). Homology of nucleotide sequences between the PCR product and corresponding regions of published pmws PCV genomes was very high. These results indicated that virus detected in this study was pmws PCV. To our knowledge, this is the first report on the presence of pmws PCV in Japan.     

犬的病料中检测到猪圆环病毒3型

为进一步弄清我国犬是否感染猪圆环病毒3型(porcine circovirus 3,PCV3),本试验对山东省青岛市某宠物医院采集发病犬的48份样品进行PCV3荧光PCR检测,发现7份病料呈现明显阳性,对这7株阳性样品继续用普通PCR扩增,有3份可以扩增出228 bp的特异性条带。这些条带测序后与圆环病毒的其他参考序列进行同源性分析,结果显示这3份样品的病毒序列与其他PCV3参考序列处于同一个进化分支,与PCV3的同源性为93.3%～99.5%,表明我国犬确实存在PCV3感染。     

猪伪狂犬病毒与猪圆环病毒2型二重SYBR GreenⅠ实时荧光PCR检测方法的建立

参照GenBank登录的相关基因序列,设计了2对引物分别用于扩增伪狂犬病毒(PRV)gH基因与猪圆环病毒2型(PCV2)ORF2基因的部分片段。将测序正确的PRV gH基因与PCV2ORF2基因片段克隆入pGEM-T Easy载体,转化大肠杆菌DH5α,经测序鉴定后得到阳性重组质粒,作为标准品模板建立SYBR GreenⅠ荧光定量PCR标准曲线和熔解曲线,并对其灵敏性、特异性和重复性进行验证。结果显示,PCV2与PRV荧光定量PCR的标准曲线的Tm值分别为80.8℃和86.7℃,熔解曲线特异,灵敏度分别可达215拷贝/μL和180拷贝/μL,是普通PCR检测方法的100倍。结果表明,建立的PCV2与PRV荧光定量PCR检测方法实现了2种病毒的同时检测,能够对PRV、PCV2混合感染的临床病料进行快速诊断。