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1.
Porcine circoviruses: a minuscule yet mammoth paradox 总被引：1，自引：0，他引：1
Ramamoorthy S Meng XJ 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2009,10(1):1-20
Porcine circovirus type 2 (PCV2) is the primary causative agent for porcine circovirus-associated disease (PCVAD). PCVAD has been the cause of considerable economic losses to the pork industry worldwide. The disease is primarily characterized by wasting, enlarged lymph nodes, jaundice and weight loss in affected weanling pigs. Several other complex syndromes involving reproductive failure, enteritis, pneumonia and necrotizing dermatitis have also been associated with PCV2 infection. Lymphoid depletion, which is the hallmark lesion of PCVAD, predisposes the host to immunosuppression. Disease progression is further complicated by co-infections with other bacterial and viral pathogens. Despite the availability of effective vaccines for the last 2 years, newly emerging strains of the virus have been reported to cause more severe outbreaks in parts of the USA and Canada. While knowledge of the biology and pathogenesis of PCV2 has progressed considerably over the last 12 years since the disease was recognized, many questions still remain to be answered. 相似文献
2.
Porcine circovirus type 2 (PCV2) infection is distributed worldwide and PCV2-associated disease (PCVAD) is considered among the most economically relevant ones to the global swine industry. PCV2 is known to play a causal role in the porcine respiratory disease complex, usually in close association with a large plethora of other biologic agents. We describe herein a case of fatal parasitic bronchopneumonia by Metastrongylus elongatus in a PCV2-infected pig. Metastrongylosis may still represent a major concern for outdoor herds. Our recent experience suggests that a concurrent PCVAD condition may trigger metastrongylosis, which may subsequently result, at its turn, in severe, sometimes fatal, pulmonary disease. 相似文献
3.
Tanja Opriessnig Xiang-Jin Meng Patrick G Halbur 《Journal of veterinary diagnostic investigation》2007,19(6):591-615
Porcine circovirus type 2 (PCV2)-associated disease (PCVAD) continues to be an important differential diagnosis on pig farms in the United States and worldwide. Case trend analyses indicate that the incidence of PCVAD is on the rise in the United States. Accurate diagnosis is important in order to implement appropriate intervention strategies. PCVAD can manifest as a systemic disease, as part of the respiratory disease complex, as an enteric disease, as porcine dermatitis and nephropathy syndrome, or as reproductive problems. PCVAD may be only a sporadic individual animal diagnosis; however, PCVAD may also manifest as a severe herd problem accelerated and enhanced by concurrent virus or bacterial infections. This article is intended to discuss the most common disease manifestations, pathogenesis, diagnostic approaches, and intervention strategies associated with PCVAD in North America. 相似文献
4.
Objective To report the occurrence and pathology of porcine circovirus type 2 (PCV2)‐associated disease (PCVAD) of postweaning pigs in two Australian pig herds. Methods Mortality data from two commercial piggeries that experienced higher than normal postweaning illthrift and mortalities were examined. Gross and histopathological examinations were performed on the index cases, and at weekly intervals thereafter for a period of 10 weeks. Specimens were submitted to the laboratory for routine diagnostic testing and for exclusion of porcine reproductive and respiratory syndrome virus (PRRSV). The genomes of two strains of PCV2 isolated during testing were sequenced. Results Mortality rates in weaned, 5–12‐week‐old pigs spiked significantly during mid to late 2007. This increase in the mortalities was mainly attributed to salmonella‐associated diarrhoea and illthrift. Salmonellosis was diagnosed in 73/110 cases inclusive of both piggeries. Many pigs also had chronic granulomatous lymphadenitis and diffuse histiocytic interstitial pneumonia consistent with PCVAD and associated with varying amounts of PCV2 antigen and inclusion bodies. All samples tested for PRRSV were negative. Sequence analysis of the PCV2 isolates showed strain differences between piggeries. Conclusion This report describes the first outbreaks of PCVAD in growing pigs in Western Australia (WA) and describes lesions not previously seen in this laboratory. It also describes the first isolation of a PCV2 group 1 virus in WA associated with PCVAD. Although the outbreaks of PCVAD occurred with concurrent salmonellosis, the two diseases were unrelated. Neither of the outbreaks met the Australian case definition for the diagnosis of postweaning multisystemic wasting syndrome. 相似文献
5.
猪圆环病毒2型靶细胞及其受体的研究进展 总被引：1，自引：0，他引：1
猪圆环病毒2型(porcine circovirus type 2,PCV2)是统称为猪圆环病毒相关疾病(porcine circovirus-associated disease,PCVAD)的几个综合征的主要致病因子。目前,对PCV2配体表位和细胞受体在病毒入侵过程中的致病机理还不清楚,受体识别是病毒黏附到宿主细胞表面的第一步,在病毒入侵和致病机理方面起到重要的作用。作者对近几年来PCV2侵染的靶细胞及其靶细胞受体的研究进展作一综述。 相似文献
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7.
猪圆环病毒2型(PCV2)感染后会导致断奶仔猪多系统衰竭综合征(PMWS)等"猪圆环病毒相关疾病"(PCVADs),给全球养猪业造成了巨大的经济损失。疫苗免疫是防控该病的有效手段,近年来市场上推出了PCV2灭活疫苗、嵌合疫苗和亚单位疫苗。PCV2变异较快,主要临床流行毒株从PCV2b逐渐演变为PCV2d,现有商业化疫苗免疫效果需进一步研究证实。论文就近年来国内外PCV2传统疫苗、新型基因工程疫苗、PCV2疫苗与其他疫苗联合免疫的研究进展进行综述,旨在为猪圆环病毒相关疾病的防控及疫苗的开发与利用提供参考。 相似文献
8.
Porcine circovirus diseases 总被引：21，自引：0，他引：21
Segalés J Allan GM Domingo M 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2005,6(2):119-142
Porcine circovirus type 2 (PCV2) is a member of the family Circoviridae, a recently established virus family composed of small, non-enveloped viruses, with a circular, single-stranded DNA genome. PCV2, which is found all over the world in the domestic pig and probably the wild boar, has been recently associated with a number of disease syndromes, which have been collectively named porcine circovirus diseases (PCVD). Postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis and nephropathy syndrome (PDNS) and reproductive disorders are the most relevant ones. Among them, only PMWS is considered to have a severe impact on domestic swine production. PMWS mainly affects nursery and/or fattening pigs; wasting is considered the most representative clinical sign in this disease. Diagnosis of this disease is confirmed by histopathological examination of lymphoid tissues and detection of a moderate to high amount of PCV2 in damaged tissues. Since PMWS is considered a multifactorial disease in which other factors in addition to PCV2 are needed in most cases to trigger the clinical disease, effective control measures have focused on the understanding of the co-factors involved in individual farms and the control or elimination of these triggers. PDNS, an immuno-complex disease characterized by fibrino-necrotizing glomerulonephritis and systemic necrotizing vasculitis, has been linked to PCV2, but a definitive proof of this association is still lacking. PCV2-associated reproductive disease seems to occur very sporadically under field conditions, but it has been characterized by late-term abortions and stillbirths, extensive fibrosing and/or necrotizing myocarditis in fetuses and the presence of moderate to high amounts of PCV2 in these lesions. Taking into account that scientific information on PCV2 and its associated diseases has been markedly expanded in the last 8 years, the objective of this review is to summarize the current state of knowledge of the most relevant aspects of PCV2 biology and PCVD. 相似文献
9.
Genomic comparison of foot-and-mouth disease virus R strain and its chick-passaged attenuated strain
Porcine circovirus type 2 (PCV2) is a single-stranded circular DNA virus that is the causative agent of porcine circovirus associated disease (PCVAD), a disease complex affecting swine around the world. Although this virus is believed to negatively affect the host's immune system, the mechanism by which PCV2 induces disease is not completely understood. This report describes a series of PCV2 experiments using the gnotobiotic pig model in which a relationship was demonstrated between abnormal leukograms and development of clinical disease in PCV2-infected pigs. When compared to control pigs the leukogram was characterized by a decrease in lymphocytes within 14 days post inoculation (dpi) followed by an increase in neutrophils 7-14 days later. No significant changes in the circulating monocyte, basophil, and eosinophil cell populations were detected. The combination of an absolute neutrophilia and lymphopenia produced a neutrophil/lymphocyte ratio that was predictive of clinical disease and was inversely correlated with the presence of neutralizing antibodies. Based on previous reports, the lymphopenia may be attributed to a direct cytolytic effect of the virus and could negatively affect the pig's immune response. The role of the neutrophilia in the pathogenesis of PCVAD in gnotobiotic pigs is unknown. 相似文献
10.
The effect of vaccination against Porcine reproductive and respiratory syndrome virus (PRRSV) on the Porcine circovirus-2 (PCV-2) load in porcine circovirus associated disease (PCVAD) affected pigs 
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下载免费PDF全文 Marika Genzow Kent Schwartz Glenda Gonzalez Gail Anderson Wayne Chittick 《Canadian journal of veterinary research》2009,73(2):87-90
A diagnostic project was initiated across the United States in 2006 to improve the understanding of porcine circovirus associated diseases (PCVAD) as well as to identify co-factors in PCVAD-affected farms. A Porcine circovirus-2 (PCV-2) DNA real-time polymerase chain reaction quantitation (qPCR) was established according to a published method and sera from a total of 23pig farms across the United States were examined for viral loads for PCV-2 and analyzed for any possible effects of Porcine reproductive and respiratory syndrome virus (PRRSV) vaccination on this parameter. Vaccination against PRRS resulted in significantly lower viral loads for PCV-2 in animals 13 wk or older compared with nonvaccinated animals, but vaccination of pigs against PRRS had no effect on qPCR results for PCV-2 in 4- to 12-week-old pigs. Interestingly, PRRS vaccinates had significantly lower viral loads when peak wasting disease was observed in the herds. The qPCR method for PCV-2 proved to be an important tool for help in the antemortem diagnosis of PCVAD as well as in the monitoring of infection dynamics. 相似文献
11.
Porcine circovirus type 2 (PCV2) is an economically important emerging pathogen associated with distinct syndromes and diseases in swine, collectively known as porcine circovirus associated diseases (PCVAD). The main purpose of this study was to investigate the presence of PCV2 in piglets affected with exudative epidermitis (EE) in Uruguay. In addition we aimed to analyze the phylogenetic relationships of the isolated strains. In June 2011 an outbreak of EE detected in a small herd was reported. Piglets presented skin lesions compatible with EE and symptoms associated with postweaning multisystemic wasting syndrome (PMWS) were also observed. Sera from affected and healthy animals were tested for the presence of viral DNA. Exclusively, diseased piglets were infected with PCV2. Phylogenetic analysis showed that PCV2 isolates belonged to PCV2b genotype. We report the detection and molecular characterization of PCV2 strains for the first time in Uruguay. 相似文献
12.
Cecere TE Meng XJ Pelzer K Todd SM Beach NM Ni YY Leroith T 《Veterinary microbiology》2012,160(1-2):233-239
Porcine circovirus associated disease (PCVAD) is currently one of the most economically important diseases in the global swine industry. Porcine circovirus type 2 (PCV2) is the primary causative agent, however co-infection with other swine pathogens such as porcine reproductive and respiratory syndrome virus (PRRSV) is often required to induce the full spectrum of clinical PCVAD. While the specific mechanisms of viral co-infection that lead to clinical disease are not fully understood, immune modulation by the co-infecting viruses likely plays a critical role. We evaluated the ability of dendritic cells (DC) infected with PRRSV, PCV2, or both to induce regulatory T cells (T(regs)) in vitro. DCs infected with PCV2 significantly increased CD4(+)CD25(+)FoxP3(+) T(regs) (p<0.05) and DCs co-infected with PRRSV and PCV2 induced significantly higher numbers of T(regs) than with PCV2 alone (p<0.05). Cytokine analysis indicated that the induction of T(regs) by co-infected DCs may be dependent on TGF-β and not IL-10. Our data support the immunomodulatory role of PCV2/PRRSV co-infection in the pathogenesis of PCVAD, specifically via T(reg)-mediated immunosuppression. 相似文献
13.
猪病的传播和流行一直是制约我国生猪养殖业发展的主要因素,特别是近年来猪病流行情况的日益复杂,非洲猪瘟、猪圆环病毒3型（Porcine Circovirus Type 3, PCV3）等多种新发疫病的不断出现,严重制约了我国生猪产业的发展,对生猪产业造成严重打击,同时也加速了我国猪场转型升级的步伐,对现代化猪场的生物安全和饲养管理提出了更高的要求。PCV3在2016年国内猪场发生至今,已传播扩散至我国多省的不同地区,成为严重威胁我国养猪业的一种新发疫病,PCV3感染导致猪群健康受损的同时,也大大增加了其他病原微生物感染的风险,且目前暂无有效疫苗对PCV3进行防控,给猪场造成了严重经济损失。本文对PCV3病原学特征、流行病学特点、临床症状和防控措施等方面进行简单综述,以期为预防PCV3的流行传播和基础研究提供参考。 相似文献
14.
Porcine circovirus type 2-associated cerebellar vasculitis in postweaning multisystemic wasting syndrome (PMWS)-affected pigs 总被引：1，自引：0，他引：1
Seeliger FA Brügmann ML Krüger L Greiser-Wilke I Verspohl J Segalés J Baumgärtner W 《Veterinary pathology》2007,44(5):621-634
Porcine circovirus type 2 (PCV2) is associated with several syndromes in growing pigs, including postweaning multisystemic wasting syndrome and porcine dermatitis and nephropathy syndrome. In the present study, a previously undescribed neurovascular disorder associated with a PCV2 infection is described. Sixteen pigs showed clinical signs of wasting and neurologic deficits. Acute hemorrhages and edema of cerebellar meninges and parenchyma due to a necrotizing vasculitis resulted in degeneration and necrosis of the gray and white matter. Few to numerous PCV2 DNA and antigen-bearing endothelial cells were detected in affected areas of the brain using in situ hybridization and immunohistochemistry. Conventional histochemical stains, as well as the detection of caspase 3 activity and DNA strand breaks by the terminal transferase dUTP nick end labeling assay, showed numerous apoptotic endothelial cells in the vascular lesions observed. Sequencing of various brain-derived PCV2-specific amplicons revealed a strong identity between different isolates and an 89 to 100% identity to previous isolates. The phylogenetic tree showed that there was no clustering of isolates correlating to clinical signs or geographic distribution. This previously undescribed PCV2-associated neurologic disease has features of both postweaning multisystemic wasting syndrome and, to a lesser extent, porcine dermatitis and nephropathy syndrome. The available evidence suggests that direct virus-induced apoptosis of endothelial cells plays a role in the pathogenesis of this unusual PCV2-associated cerebellar vasculitis. 相似文献
15.
为掌握酒泉市五个农业县猪圆环病毒2型（PCV2）和3型(PCV3)流行情况,在辖区内不同区域、不同养殖规模、不同生长阶段的19个规模化养殖场、38个散养户、4家屠宰场采集血清样品230份、粪便样品250份、猪肺脏、扁桃体、颌下淋巴结等组织样品220份,进行PCV2和PCV3核酸检测,检出阳性样品138份,阳性率为21.23%,PCV2的阳性率为15.54%,PCV3的阳性率为5.69%,表明PCV2的流行比PCV3更普遍、阳性感染率更高,但在不同区域、不同规模猪场的危害程度和流行情况存在一定的差异。规模养殖场的总体阳性感染率明显低于散养户,保育猪的感染率高于其他生长阶段的生猪。本次实验对酒泉市猪场PCV感染综合防控提供技术支撑,为科学养猪产生积极影响。 相似文献
16.
Tanja Opriessnig John R. Prickett Darin M. Madson Hui-Gang Shen Nicole M. Juhan Roman M. Pogranichniy Xiang-Jin Meng Patrick G. Halbur 《Veterinary research》2010,41(3)
Long-term PCV2 infection and/or concurrent infection with genotypes PCV2a and PCV2b may play a role in the development of clinical porcine circovirus-associated disease (PCVAD). To evaluate this premise, 24 11-week-old specific pathogen-free (SPF) pigs were randomly assigned to 1 of 4 treatments: negative controls, a single inoculation with PCV2a, single inoculation followed by re-inoculation with a homologous PCV2a strain, or repeated inoculations with heterologous strains (PCV2a, PCV2b). Pigs were evaluated for clinical signs daily through 140 days post inoculation (dpi). Serum samples were collected every other day from dpi 0 through 14 and weekly thereafter. PCV2-inoculated pigs were viremic by dpi 2 and 13 of 18 pigs remained viremic at 140 dpi. No statistical differences in the onset, level, or duration of PCV2 viremia were detected among treatment groups. Anti-PCV2 antibodies were detected between 14 and 28 dpi and were present through 140 dpi without statistical differences in antibody response among treatment groups. In the current study, pigs had extended viremia combined with detectable tissue PCV2 antigen levels despite the presence of high levels of anti-PCV2 antibody; however, no clinical disease was observed. 相似文献
17.
猪圆环病毒2型感染的血清学分析 总被引：37，自引：5，他引：37
应用间接免疫荧光技术 ,测定了浙江省内 4 4个猪场 2 0 0 0～ 2 0 0 2年间的 2 0 39个血清样本 ,对不同地区、年龄和品种猪的血清学数据进行了系统分析。结果显示 ,浙江省 4 4个猪场均有猪圆环病毒 2型 (PCV2 )感染 ,猪场的感染率为 10 0 % ,全省猪的 PCV2感染的平均血清阳性率为 5 8.31% ,其中种猪感染的血清阳性率为 5 9.38% ,断奶后猪感染的血清阳性率为 5 6 .6 5 %。长白种猪感染的血清阳性率为 4 4 .83%、长白仔猪感染的血清阳性率为 6 4 .2 8% ,明显高于大约克和杜洛克种猪和仔猪的感染率。 PCV2感染的血清阳性率高的种猪和仔猪群 ,其 PRRSV和 Pr V的抗体阳性率低。这些结果说明 ,PCV2在猪群中的感染非常普遍 ,不同品种猪对 PCV2的易感性不同 ,PCV2的感染可降低猪群对疫苗的免疫应答 相似文献
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猪圆环病毒2型(PCV2)是引起猪圆环病毒病相关疾病的主要致病原,可损伤宿主的免疫系统,加剧一些细菌病和病毒病感染的临床症状,在全球养猪业中造成巨大损失。PCV2的基因组DNA含有11个开放阅读框(ORFs),其中至少有7个ORFs编码的蛋白质分子质量大于5ku,但目前只有5种编码的蛋白(Rep、Rep'、Cap、ORF3和ORF4)发现于PCV2复制过程中。作者概述了当前PCV2基因组DNA的结构与功能,阐明PCV2的病原学,为防控PCV2感染提供科学依据。 相似文献
19.
Porcine circovirus type 2 (PCV2) is a disease caused by porcine circovirus, which can damage the host's immune system and exacerbate the clinical symptoms of many bacterial and viral infections.It has caused increasingly larger losses in the pig industry wordwide.The genomic DNA of PCV2 contains 11 open reading frames (ORFs) and at least seven potential ORFs-encoding proteins larger than 5 ku.However, only five virally encoded proteins, including Rep, Rep', Cap, ORF3 and ORF4, had been identified in PCV2 replication.In this review, we discussed the progress on structure and function of genomic DNA of PCV2 in order to provide insight into the scientific basis of the pathogenesis of PCV2 and prevent its infection. 相似文献