豫南地区规模化猪场猪繁殖与呼吸综合征病毒和猪圆环病毒2型抗体检测与分析

为掌握豫南地区规模化猪场中猪繁殖与呼吸综合征病毒（PRRSV）和猪圆环病毒2型（PCV2）疫苗免疫场猪群抗体水平和非疫苗免疫场猪群病原感染情况,试验利用ELISA方法对该地区猪群进行了PRRSV和PCV2抗体水平检测。结果表明,在疫苗免疫猪群中,PRRSV和PCV2抗体合格率分别为68.8%和58.7%,规模越大的猪场合格率越高,200~500头母猪规模场抗体阳性率最高（分别为76.8%和77.4%）,50头母猪以下场最低（分别为48.3%和44.2%）,种猪的合格率均最高,而育肥猪群合格率均最低。在非疫苗免疫猪群中,PRRSV和PCV2抗体阳性率分别为55.6%和65.3%,PRRSV抗体阳性率最低的是100~200头母猪规模场（46.5%）,最高的是50头母猪以下规模场（68.8%）,断奶仔猪和育肥猪群抗体阳性率均在71%以上;随猪场规模越大,PCV2抗体阳性率越低,200~500头母猪规模场抗体阳性率为41.4%,50~100头规模场和50头以下场的阳性率分别为78.9%和78.6%,种公、母猪的PCV2抗体阳性率最低（分别为37.5%和40.4%）,断奶仔猪和育肥猪抗体阳性率较高（分别为82.2%和79.5%）。本研究反映了豫南地区猪繁殖与呼吸综合征（porcine reproductive and respiratory syndrome,PRRS）和猪圆环病毒病（porcine circovirus disease,PCVD）疫苗免疫猪场的疫苗免疫效果和非疫苗免疫猪场病原感染的实际情况和规律,为该地区PRRS和PCVD防制工作提供了理论依据和指导。     

猪圆环病毒2型(PCV2)在产房由母猪传染给仔猪的研究

<正>猪圆环病毒2型(PCV2)是猪圆环病毒相关疾病(PCVD)的病原,广泛分布于世界各地的养猪场。原来认为猪在10~15周龄感染PCV2,当出现病毒血症时几乎所有的肥育猪都已感染。仔猪断奶前后免疫PCV2疫苗可有效地预防PCVD和降低PCV2病毒血症水平,但不能根除感染。既然疫苗免疫不能彻底消除感染,肥育猪还带毒,这表示后备母猪和经产母猪可能感染PCV2并且可能在子宫内或者分娩后传染给仔猪。因此,美国中西部的一个母猪养殖场开展了一     

猪群免疫圆环病毒苗的理由

正我国自2000年首次报道猪群中存在PCV2感染的血清学证据以来,猪群中PCV2感染十分普遍,各地区陆续报道,流行范围波及全国,猪群平均阳性率38.47%,猪场阳性率58.75%以上。猪圆环病毒病(PCVD)是困扰养猪业的一个重要问题,广大养殖场户对是否免疫圆环病毒疫苗始终存在困惑,本人就这个问题进行相关探讨。1圆环病毒的病原学特点猪圆环病毒病(PCVD)是继猪繁殖与呼吸综合征(PRRS)之后新发现的猪重要传染病,是由猪圆环病毒(PCV)引起的一类疾病的总称。PCVD是能够     

猪圆环病毒病

猪圆环病毒病（PCVD）是指一种由圆环病毒科、圆环病毒属的猪圆环病毒（Porcinecircovirus，PCV）所引起的哺乳仔猪和育肥猪的临床或亚临床型传染病。猪圆环病毒是一种高度异质的单股环状DNA病毒，具有严格的种属和组织特异性，主要感染猪的皮肤和粘膜组织，引起相应部位上皮组织的增生性病变，猪圆环病毒还能加重猪呼吸和繁殖障碍综合征病毒（PRRS），猪细小病毒（PPV）等感染。现已确认猪圆环病毒病（PCVD）发生于全世界，对养猪业带来了严重的经济损失。从而本文对猪圆环病毒的病原学、流行病学、临床症状、病理变化、诊断、治疗及防制措施等作一简要概述。     

PCV2疫苗对有PCV相关疾病史的猪群在育肥期生长性能、胴体品质和死亡率影响的田间评估

试验目的是评估猪圆环病毒2型（PCV2）疫苗对育肥猪生长性能和死亡率的影响。研究采用2X2析因试验设计,根据PCV2疫苗免疫与否分为免疫与对照2个水平。根据性别分为去势公猪和小母猪2个水平。不同性别的猪（PICL337X1050）被随机分为疫苗免疫组和未免疫对照组。本研究主要分为两个试验,即试验一,在猪9周龄和11周龄时接种疫苗;试验二,在猪5周龄和7周龄时接种疫苗。从11周龄开始,对试验期间育肥猪的生长性能数据进行采集。记录每栏的猪体重和日采食量。     

猪圆环病毒-支原体二联疫苗（诗圆静）免疫攻毒试验

<正>猪圆环病毒2型（PCV2）和猪肺炎支原体（M.hyo）是世界范围内影响猪群健康和给牧场带来严重经济损失的两种主要病原。PCV2是猪圆环病毒相关疾病（PCVD）的主要病原,感染可导致明显的临床症状如种猪繁殖障碍以及生长育肥猪生长迟缓、日增重降低、料重比升高,并发其他疾病,导致死亡率增加;也可能不表现症状,呈亚临床感染状态,导致猪群生长速度变慢,严重影响经济效益。M.hyo是猪慢性呼吸道疾病的主要病原,     

新疆北疆地区某规模化猪场主要传染病抗体检测与分析

为了解新疆北疆地区某规模化猪场几种主要传染病的抗体水平,便于及时发现猪场潜在的疾病风险。本试验采用间接酶联免疫吸附试验（ELISA）方法对某规模化猪场各阶段猪群进行猪瘟病毒（CSFV）抗体、猪繁殖与呼吸障碍综合征病毒（PRRSV）抗体、猪圆环病毒2型（PCV2）抗体、猪O型口蹄疫病毒（FMDV-O）抗体,及猪伪狂犬病病毒（PRV）gB与gE蛋白抗体进行检测。试验结果表明,该场的CSFV、PRRSV、PCV-2、FMDV-O、PRV-gB蛋白、PRV-gE蛋白的平均抗体阳性率分别为83.57%、90.56%、90.29%、71.86%、82.84%、18.29%;不同类别猪群间抗体水平参差不齐,种猪群的PRRSV抗体阳性率仅为52.63%,保育猪群的CSFV抗体阳性率仅为44.12%,育肥猪群的PRV-gB抗体阳性率为30.00%,种公猪的PRV-gE抗体阳性率为30.00%,育肥猪群的FMDV-O抗体阳性率为6.25%,基于以上试验结果,为该场免疫程序的制定和优化提供参考依据,以期达到有效控制及逐渐净化疫病的目的。     

猪圆环病毒2型的感染特点、抗体分析及疫苗效果评估

<正>自2010年以来,猪圆环病毒病(PCVD)的防控逐渐成为猪场疾病控制的重点,且商品化的圆环病毒疫苗大量推广,从整体来看,疫苗对圆环病毒病以及整个猪群的疾病防控具有较好效果。2011-2012年猪群整体上没有发生大的疫情,卫秀余老师认为这得益于圆环病毒疫苗的大量推广和使用。本文对圆环病毒的感染特点、抗体分析和疫苗效果评估进行简要分析,以期为圆环病毒病的防控提供借鉴和帮助。1猪圆环病毒病的感染特点猪圆环病毒2型(PCV2)可引起断奶仔猪多系统衰竭综合     

重庆地区猪圆环病毒病的流行状况及分析

猪圆环病毒病（PCVD）主要是由猪圆环病毒2型（PCV-2）引起的猪传染性疾病,是继猪繁殖与呼吸障碍综合征（PRRS）之后新发现的又一重要疫病。其病毒为圆环病毒科圆环病毒属成员,有两种基因型,即PCV-1和PCV-2。PCV-1无致病性;PCV-2可引起断奶仔猪多系统衰竭综合征（PMWS）,还可导致母猪繁殖障碍、断奶和育肥猪的呼吸道疾病、猪肾炎与皮炎综合征（PDNS）以及猪的先天性震颤。特别是2005年后在北美暴发流行以来,PCV2感染引起的相关疾病已成为各国学者研究的焦点;2008年第20届国际猪病大会上,人们已将PCVD列为当前危害养猪业发展的头号疾病。     

2008～2010年华东部分地区猪圆环病毒2型感染血清学调查

为了解华东地区近三年来猪圆环病毒病（porcine circovirus disease,PCVD）的流行状况,以便更好地控制该病的发生,2008年1月～2010年9月在华东地区5个省、直辖市及河南省的68个规模化猪场（均未免疫商品化猪圆环病毒疫苗）共收集1017份猪血清样品,应用商品化猪圆环病毒（Porcine circovirus,PCV）抗体诊断试剂盒（PCV2-ELISA）,对送检血清样品进行PCV2抗体水平检测。结果显示：送检猪血清中抗体阳性总数为609份,总阳性率为59.88%;2008、2009和2010年送检样品的阳性率分别为53.4%、35.33%和80.63%,PCV血清抗体阳性率呈先下降后上升的趋势;成年猪血清阳性率最高为81.40%,保育猪血清阳性率最低为41.48%,仔猪和育肥猪血清阳性率相近,分别为57.95%和52.20%,说明仔猪断奶后随母源抗体下降其抗体阳性率亦下降,但随猪龄的增长而感染逐渐加重后其抗体阳性率又升高,且不同生长阶段PCV毒抗体阳性率有明显差异。     

One dose of a porcine circovirus 2 subunit vaccine induces humoral and cell-mediated immunity and protects against porcine circovirus-associated disease under field conditions

This study investigated the efficacy of a one-dose porcine circovirus 2 (PCV2) subunit vaccine based on the PCV2 Cap protein expressed in a baculovirus system on two different farms at which a history of porcine circovirus-associated disease (PCVD) was present. Morbidity, mortality, average daily weight gain, carcass weight, PCV2 load in serum and vaccine immunogenicity were assessed. Serology to porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae was performed. A double-blind, randomised, and controlled field trial was performed distributing 818 piglets between two treatment groups. At inclusion (weaning at 21 ± 3 days of age), 408 animals (group B) received a 2-mL intramuscular dose of Porcilis PCV(?) (vaccinated group). Controls (group A, 410 pigs) received 2 mL of the adjuvant Diluvac Forte(?) intramuscularly. Weights were recorded at inclusion and at 12 and 26 weeks of age, and the average daily weight gain (ADWG) was calculated. The carcass weights of the pigs from farm 2 were recorded at slaughter (274 days old). All dead animals (died or culled) underwent autopsy to classify them as PMWS-affected or not. At each farm, blood samples were taken from 22 pigs/group for serologic studies. A beneficial effect was found after vaccination with a single dose of a PCV2 Cap vaccine against PCVD. The vaccination reduced the mortality rate and morbidity, reduced PCV2 viremia and viral load, improved productive performances (e.g. ADWG: +70 g/day between 12 and 26 weeks of age when viremia and the specific disease occurred) as well as carcass weight at slaughter age (+4.5 kg). These effects were associated with virologic and clinical protection from the immunogenicity of the vaccine measured as activation of both a humoral and a cellular immune response.     

规模化自繁猪场猪圆环病毒病的流行特点和防控措施

猪圆环病毒2型（porecine circovirus type 2,PCV2）是猪圆环病毒病（porcine circovirus diseases,PCVD）的主要病原,该病流行范围广,感染率高而表现临床症状少,是一种缓慢、渐进性的综合征,多为隐性感染,常常存在多因子诱因,一旦发病反复迁延、病程延长,造成较大的经济损失。对规模化自繁猪场PCVD的流行特点、病因分析等方面进行了阐述,以期为PCVD的防控提供参考。     

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.     

The detection of porcine circovirus in the Australian pig herd

OBJECTIVE: To determine if porcine circovirus (PCV) type 1 (PCV1) or type 2 (PCV2) is present in the Australian pig herd, to conduct preliminary genetic characterisation of any viruses detected, and to determine if there is any obvious virological reason why post-weaning multisystemic wasting disease (PMWS), associated with PCV infection in other countries, has not been detected in Australia. DESIGN: Serum samples were collected from 14 randomly selected pig farms in Western Australia and used for detection of PCV antibody. Additional samples from one farm were obtained at 2-week intervals from pigs between 2 and 12 weeks of age to detect any age-associated variations in prevalence of infection. Veterinary practitioners from four Australian states submitted tissues of dead or unthrifty weaned pigs, and these were examined for evidence of PCV1 and PCV2 infection. PROCEDURE: Sera were tested for antibody to PCV using an indirect immunofluorescence assay (IFA). Tissues were tested for PCV1 and PCV2 genomic material using a multiplex PCR. RESULTS: PCV antibody was detected in approximately 30% of Western Australian pigs tested. PCV1 DNA was detected in tissue samples from Western Australia, South Australia and New South Wales and PCV2 DNA was detected in tissue samples from Western Australia, New South Wales and Queensland. Sequence analysis of the PCR products indicated the PCV1 and PCV2 present in Australia were very similar to strains in other countries where PMWS is endemic. CONCLUSION: Both PCV1 and PCV2 are present in Australia and the viruses present appear similar to those in countries with PMWS. The absence of PCV2-associated PMWS in Australia may be due to absence of essential secondary factors required for PCV2 to produce PMWS.     

Shedding pattern and serological profile of porcine circovirus type 2 infection in cesarean-derived, colostrum-deprived and farm-raised pigs

Six 5-week-old porcine circovirus type 2 (PCV2)-free, cesarean-derived, colostrums-deprived (CDCD) pigs were inoculated intranasally with 10(6) TCID(50) of PCV2. Four CDCD pigs were untreated cohabitants. Forty farm-raised pigs from two PCV2-contaminated herds were randomly selected for PCV2 trace investigations. Blood, nasal, oropharyngeal and fecal samples were collected from all tested pigs weekly. The PCV2 DNA shed at 6-11 and 7-12 weeks of age for PCV2-inoculated pigs and cohabitants, respectively. All the CDCD pigs exhibited seroconversion after PCV2 exposure. In the farm-raised animals, PCV2 shed at 9-15 weeks of age and seroconversion started at 11 weeks of age. Collectively, the pigs had a prolonged PCV2 shedding period following viral exposure, and growing pigs were the source of horizontal PCV2 transmission in PCV2-infected herds.     

A field evaluation of mortality rate and growth performance in pigs vaccinated against porcine circovirus type 2

OBJECTIVE: To evaluate, under field conditions, the effects of a commercial porcine circovirus type 2 (PCV2) vaccine on mortality rate and growth performance in a herd infected with PCV2 that had a history of porcine circovirus disease. DESIGN: Randomized controlled clinical trial. ANIMALS: 485 commercial, cross-bred, growing pigs. PROCEDURES: Prior to weaning, pigs were randomly assigned within litter to a vaccination or unvaccinated control group. Pigs in the vaccination group were given a commercial PCV2 vaccine at weaning and 3 weeks later. Mortality rate was recorded, and pigs were weighed prior to vaccination, when moved from the nursery, and prior to marketing. Infection status was assessed by serologic testing and detection of viral DNA in serum. RESULTS: Compared with control pigs, pigs vaccinated against PCV2 had a significantly lower mortality rate during the finishing phase, significantly higher average daily gain during the finishing phase, and significantly lower likelihood of being lightweight at the time of marketing. For vaccinated pigs, overall mortality rate was reduced by 50% and average daily gain during the finishing period was increased by 9.3%. At the time of marketing, vaccinated pigs weighed an average of 8.8 kg (19.4 lb) more than control pigs, without any difference in days to marketing. Serum PCV2 antibody titers increased in control pigs, and PCV2 DNA was detected, indicating active PCV2 infection. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that vaccination against PCV2 was effective at reducing mortality rate and improving growth performance among pigs in a herd infected with PCV2.     

Comparison of Porcine circovirus type 2 (PCV2) infection in light and heavy pigs of market age on farms with routine PCV2 vaccination

Commercial vaccines against Porcine circovirus type 2 (PCV2) are widely used on swine farms. Marked body weight variation at marketing age is a problem on conventional pig farms using all-in/all-out barn management. The aim of this study was to investigate whether PCV2 infection could be a factor influencing body weight variation. Seven conventional farms that routinely used PCV2 vaccination were selected, and 60 serum samples from light and heavy pigs at each site were tested for PCV2 antibody titers and viremia. At 3 farms the mean antibody titer, proportion of viremic pigs, and virus load differed significantly between the light and heavy groups. These preliminary results suggest that PCV2 infection may be a factor contributing to weight variation in vaccinated market-age hogs.     

Porcine circovirus diseases

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.     

Detection of Porcine circovirus type 2 viremia and seroconversion in naturally infected pigs in a farrow-to-finish barn

Porcine serum was assayed by 2 polymerase chain reaction (PCR) protocols (nested PCR [nPCR] and non-nested PCR) and a competitive enzyme-linked immunosorbent assay to determine when Porcine circovirus type 2 (PCV2) viremia and a rise in the serum level of PCV2-specific antibody occurred in pigs raised in a large Canadian farrow-to-finish barn. Eight serial blood samples were collected from each of 40 pigs from 5 to 156 (+/- 1.5) d of age; 6 pigs were removed from the study for various reasons at various times. Viremia was not detected in the samples collected before 72 d of age but was detected in those collected on or after 72 d: of 33 pigs, 7 (21%) had only 1 serum sample positive for PCV2 DNA by nPCR after day 72; 11 (33%) were intermittently positive by nPCR, non-nested PCR, or both between 72 and 156 d; and the remaining 15 (45%) were repeatedly positive (in 2 to 4 samples). The level of serum antibody against PCV2 declined after weaning and increased between 72 and 107 d of age, only after PCV2 was detected in serum. Our results show that PCV2 viremia persists in the presence of elevated levels of PCV2-specific antibody.