PCV2相关疾病(PCVDs):风险因素分析

1 PCV2感染动力学的重要性:猪感染PCV2时的年龄是决定因素 累积的证据表明,猪场内PCV2感染动力学在很大程度上与PCVD发病的机率有关.在法国(2000 ～ 2001年)和西班牙(2002 ～ 2003年)进行的第一个病例对照研究表明,PCVD发病猪场内12～ 13周龄猪群的PCV2血清阳性率要高于非发病猪场的猪群.这证实了PCVD发病猪场的PCV2感染的平均发生时间较早.在PCVD发病猪场进行的更详细研究(纵向队列研究)后,证实了PCV2感染的发生时间越早,猪爆发PCVD的风险越大(图1).     

猪圆环病毒病快速检测的应用研究与流行病学调查

本研究对2012年4月至2013年3月上海市浦东新区5个规模化养殖场进行了猪圆环病毒（Porcine circovirus,PCV）2型（PCV2）针对性的调查,并对PCV2疑似病例进行病原和其他病原混合感染状况调查.浦东地区发病猪群PCV2阳性率平均为31.5％.研究表明,浦东地区PCV2与猪繁殖与呼吸综合征病毒（Porcine reproductive and respiratory syndrome,PRRSV）的混合感染率为34.8％,混合感染是导致猪群死亡的重要因素,也是当今浦东地区猪群疫病的感染现状及发病模式.     

猪圆环病毒与断乳仔猪多系统衰竭综合征

断乳仔猪多系统衰竭综合征是由猪圆环病毒2型感染所致的一种新的病毒性疾病．近几年来给养猪业发达的国家造成了相当大的经济损失，已成为危害养猪生产的主要疾病之一。PCV-2感染除了引起PMWS而外，还可导致母猪繁殖障碍、断奶猪和育肥猪的呼吸道疾病、猪皮炎和肾病综合征以及猪的先天性震颤。迄今。PCV-2感染和引起的疾病已呈全球分布，日益受到人们的关注。2001年王忠田等通过对北京、天津、广东、深圳、山东、山西等地规模化猪场PCV-2感染发病群猪进行了临床发病情况调查，并采用PCR方法对所收集的55份组织病料进行PCV-2的检测，结果表明，12个猪场中有11个猪场发病猪群表现为断奶后多系统衰竭综合征，1个猪场表现为皮炎和肾病综合征。由此可见，PCV-2感染在我国规模化猪场已普遍存在，对该病的控制应引起足够的重视。     

“猪圆环病毒Ⅱ型”专栏二：PCV2相关疾病（PCVDs）：风险因素分析

1 PCV2感染动力学的重要性：猪感染PCV2时的年龄是决定因素累积的证据表明,猪场内PCV2感染动力学在很大程度上与PCVD发病的机率有关。在法国（2000～2001年）和西班牙（2002～2003年）进行的第一个病例对照研究表明,PCVD发病猪场内12～13周龄猪群的PCV2血清阳性率要高于非发病猪场的猪群。     

猪圆环病毒2型感染的血清学分析

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     

四川省部分地区猪圆环病毒2型流行病学调查

以四川省7个市县地区14个猪场为研究对象,采集疑似圆环病毒2型感染的死猪、病料、精液、血样等样品181份,进行PCR检测。结果显示:猪圆环病毒2型(PCV2)阳性有89份,阳性率49.2%;14个规模化猪场中均检测出了PCV2阳性。在死亡的43头猪中有21头PCV2阳性。病料中PCV2的阳性检出率54.0%。该病在春夏季节感染率最高,并存在病毒混合感染和继发细菌感染情况。根据临床症状和病理变化分析,大部分猪场因感染PCV2而致断奶仔猪多系统衰竭综合征(PMWS),其中遂宁市和绵阳市的6个规模化猪场中检测到PCV2感染所引起的猪皮炎肾病综合征(PDNS)。结果表明,四川省部分地区的规模化猪场中已经广泛存在猪圆环病毒2型感染。     

规模化猪场猪圆环病毒2型的血清流行病学调查

为了解规模化猪场猪圆环病毒2型(PCV2)血清学流行情况,采用ELISA进行PCV2抗体检测。结果表明,运城地区规模化猪场广泛存在PCV2感染,未免疫接种猪圆环病毒疫苗的外观健康猪血清样品中PCV2抗体平均阳性率为49.66%,其中种猪感染率达67%,哺乳仔猪感染率4.55%,保育猪感染率43%,育肥猪感染率64.71%;外观健康猪群检测结果提示,随着年龄的增长PCV2感染有升高趋势。为了进一步研究猪圆环病毒感染各症候群在规模化场发病特点及流行规律,采集临床疑似断奶仔猪多系统衰竭综合征(PMWS)、仔猪先天性震颤(Congenital tremors,CT)、猪肾炎皮炎综合征(PDNS)、猪的繁殖障碍(Reproductive failure)、PCV2相关性肺炎等症状猪血清400份进行PCV2抗体检测。检测结果显示,疑似PMWS症状PCV2抗体阳性率最高,达86.25%,然后依次是疑似PCV2相关性肺炎阳性率56.25%,疑似PDNS阳性率46.25%,疑似繁殖障碍阳性率26.25%,最低的是疑似CT阳性率11.25%。研究结果表明,运城地区规模化猪场PCV2感染以PMWS和PCV2相关性肺炎为主,其次是PDNS和繁殖障碍,仔猪先天性震颤感染率最低。     

致陆良县哺乳仔猪腹泻病原分析

哺乳仔猪腹泻病是养猪生产中常见的疾病之一,该病严重影响仔猪的成活率和养猪业的健康发展.涉及云南省陆良县5个规模化猪场的152份发生仔猪腹泻病的病料,检测了大肠杆菌、沙门氏菌、猪传染性胃肠炎病毒(TGEV)、猪流行性腹泻病毒(PEDV)、猪圆环病毒(PCV)和猪伪狂犬病毒(PRV).结果表明:陆良县规模化猪场仔猪腹泻的主要病原是大肠杆菌和PCV,5个猪场中,有2个猪场混合感染大肠杆菌和沙门氏菌,1个猪场混合感染大肠杆菌、PCV和PEDV,1个混合感染大肠杆菌、沙门氏菌和PCV,1个混合感染大肠杆菌、沙门氏菌、PCV和PEDV.综上所述,引起云南省陆良县规模化猪场仔猪腹泻病的主要病原可确定为PCV和大肠杆菌,同时部分猪场存在大肠杆菌、沙门氏菌、PCV、PEDV的混合感染,必须引起相关部门和猪场业主的高度重视.     

一例猪圆环病毒病2型和大肠杆菌病混合感染的诊断

猪圆环病毒病是指以圆环病毒-2型（PCV2）为主要病原,单独或混合感染。它是断奶仔猪多系统衰竭综合征的主要病原,一般于断奶后2～3 d或1周发病,急性发病猪群中,病死率可达10%。大肠杆菌主要是一种条件性致病菌,其中以仔猪黄白痢最为常见。2016年3月份,某猪场1月龄仔猪突然发病,病死率较高,送检病猪3头进行病因诊断。为了解该规模化猪场疫病的感染状况,通过该猪场猪群发病情况及剖检病理观察,初步判断该猪场发病猪疑似为猪瘟病毒、猪圆环病毒2型或细菌感染,通过进一步分子生物学检测及细菌分离培养与鉴定,确诊该猪场发病猪为猪圆环病毒2型和大肠杆菌混合感染。     

混合感染猪繁殖与呼吸综合征和圆环病毒2型猪群的猪瘟抗体变化研究

本试验研究旨在探究猪场发生猪繁殖与呼吸综合征(PRRS)与圆环病毒2型(PCV2)混合感染后,猪群的猪瘟抗体变化,运用RT-PCR、实时荧光RT-PCR与PCR方法,对四川某规模化发病猪场进行高致病性PRRS、猪瘟与圆环2型的病原检测。结果显示高致病性PRRS、圆环2型和猪瘟阳性率分别为54%(19/35)、50%(17/34)、0(0/5)。结合临床症状、病猪剖检变化,确诊为PRRSV与PCV-2混合感染。采集PRRS与PCV-2混合感染病猪血清12份为试验组,本场健康猪只(无临床症状、抗原检测阴性)12份为对照组,运用ELISA试验检测猪群猪瘟抗体,结果显示试验组的猪瘟抗体合格率为33%(4/12),显著低于健康对照组的合格率83.3%(10/12)(P0.05),结果表明PRRS和PCV2混合感染会对猪瘟抗体产生负面影响。     

Monitoring Analysis of Common Swine Disease in Partial Areas of Guangxi in 2014

To understand the current status of common swine diseases in Guangxi, total 325 pig tissue samples were collected from morbidity farms and slaughter houses.CSFV, PRRSV and PEDV were detected by RT-PCR, PCV2 and PRV were detected by PCR.The results showed that the infection rates of those viruses in morbidity farms were 12.00%, 28.57%, 19.43%, 53.71% and 9.71%, respectively, and in the slaughter houses were 5.33%, 2.67%, 5.33%, 59.33% and 11.33%, respectively.The rate of PCV2 coinfection with other virus was the highest.In the morbidity farms, PRRSV+PCV2 was the most universal double infection, which was 11.43%, posteriorly was PEDV+PCV2, CSFV+PCV2 and PCV2+PRV, which were 5.71%, 4.00% and 4.00%, respectively, and PRRSV+PEDV+PCV2 and PRRSV+PCV2+PRV were the most universal tripartite infection, both of them were 2.29%.In the slaughter houses, PCV2+PRV was the most universal double infection, which was 3.33%, CSFV+PCV2+PRV was the most universal triple infection, which was 0.67%.These results indicated that PCV2 had the highest infection rate not only in morbidity farms but also in slaughter houses.PCV2 coinfection with other virus was universal.The infection rate of PRV has risen.It was important to enhance the surveillance of PCV2 and PRV for the control of swine disease in Guangxi.     

江西地方株猪圆环病毒感染的检测

对江西25个猪场有明显PMWS症状猪采集的病料,用PCR-RFLP(限制性片段长度多态性)技术检测猪圆环病毒1型、2型(PCV1、PCV2)。结果PCV2的阳性率为45％,PCV1的阳性率为40％,其中有3例仅为PCV2阳性,有1例仅为PCV1阳性,推测江西不仅存在PCV的感染,且感染率也较高。     

An ORF2 protein-based ELISA for porcine circovirus type 2 antibodies in post-weaning multisystemic wasting syndrome

Porcine circovirus type 2 (PCV2) plays a crucial role in the pathogenesis of post-weaning multisystemic wasting syndrome (PMWS) in swine. As PCV2 displays significant homology with PCV1 (a non-pathogenic virus) at the nucleotide and amino-acid level, a discriminative antigen is needed for specific serological diagnosis. The ORF2-encoded capsid protein from PCV2 was used to develop an indirect enzyme-linked immunosorbent assay (ELISA). GST-fused capsid protein from PCV2 and GST alone (both expressed in recombinant baculovirus-infected cells) were used as antigens for serodiagnosis. The specificity of the ELISA for detection of PCV2 antibodies was demonstrated in sera from pigs experimentally infected with PCV1, PCV2 and other swine viruses. The semi-quantitative nature of the test was evaluated versus an immunoperoxidase monolayer assay (IPMA). The ELISA was performed on 322 sera from pigs in eight Brittany herds and compared with IPMA. The sensitivity (98.2%) and specificity (94.5%) of this test were considered suitable for individual serological detection. High PCV2 seroprevalence was found in sows and pigs at the end of the growth phase (18-19 weeks) in all eight herds. The seroprevalence in piglets (11-17 weeks) was statistically correlated with clinical symptoms of PMWS (93% in affected versus 54%, in non-affected farms). A cohort study performed in PMWS-free farms showed that 57% of piglets exhibited active seroconversion after 13 weeks, indicating that PCV2 infection occurred earlier in PMWS-affected piglets.     

猪全血中多种病原流行病学监测的初步研究

本文利用PCR或RT-PCR技术连续两年对规模猪场采集的猪全血分别进行猪瘟病毒（CSFV）、猪繁殖障碍综合征病毒（PRRSV）、猪伪狂犬病病毒（PRV）、猪圆环病毒2型（PCV2）、牛病毒性腹泻病毒（BVDV）和日本乙型脑炎病毒（JEV）的检测,结果发现2008年猪全血中CSFV、PRRSV、PRV、PCV2的感染率为30.0%、50.0%、4.0%和30.0%,2009年猪全血中CSFV、PRRSV、PRV、PCV2、BVDV和JEV的感染率分别为19.8%、13.7%、1.1%、31.9%、0.7%和2.7%,这表明用猪的全血可进行猪瘟等6种疫病的监测和流行,为更深入研究疫病的流行病学奠定了基础。     

湖北省武汉市大型规模化猪场猪圆环病毒2型流行病学调查

为掌握猪圆环病毒2型(porcine circovirus type 2,PCV2)在湖北省武汉市大型规模化养猪场的流行率,并探索该病的传播风险因素,从而为科学防控该病毒提供依据,2020年4—6月采取二阶段随机抽样方法,采集猪口腔液样品进行PCV2核酸检测。第一阶段,对武汉市所有大型规模化猪场,采用估计流行率的样本量计算方式,确定抽样场数后随机抽取猪场;第二阶段,在猪场内采取发现疫病的样本量计算方式,以栏舍为单位,计算需要随机抽取的栏舍数量。同时以调查问卷方式,对场点感染PCV2有关的风险因素进行调查。结果显示:共采集22个大型规模化猪场的330份猪口腔液样本进行检测,其中8个场的55份样本检出PCV2核酸阳性,场群表观流行率为36.4%,真实流行率为38.0%(95%CI,17.5%~58.5%),阳性场点分布在5个区(全部共6个区);净道、污道不分开是场内PCV2感染的主要风险因素。结果表明,武汉市大型规模猪场的PCV2场群流行率较高,分布范围较广,各场需加强生物安全管理,以控制PCV2的流行与传播。     

Temporal distribution of porcine circovirus 2 genogroups recovered from postweaning multisystemic wasting syndrome affected and nonaffected farms in Ireland and Northern Ireland.

Porcine circovirus type 2 (PCV2) is now recognized as the essential infectious component of porcine postweaning multisystemic wasting syndrome (PMWS). PMWS was first recognized in high-status, specific pathogen-free pigs in Canada in 1991 and is now an economically important disease that affects the swine industry around the world. Recently, reports of genomic studies on PCV2 viruses indicated that 2 distinctive genogroups of PCV2 exist.4,10 This report involves the results of a study on the distribution of predominant PCV2 genogroups recovered from samples taken from PMWS-affected and PMWS-nonaffected farms on the island of Ireland over a 9-year period and the results of a study on PCV2 genogroup recovery from fecal samples taken from a farm in Northern Ireland from 2003 to 2005 that was first diagnosed as PMWS positive in August 2005. The results indicate that, although at least 2 distinct genogroups of PCV2 have been circulating on pig farms on the island of Ireland, there does not appear to be a direct relationship between infection with these different genogroups of PCV2 and the development of PMWS.     

Detection and genetic characterization of porcine circovirus type 2 (PCV2) in pigs from Croatia

Porcine circovirus type 2 (PCV2) from the Circoviridae family has recently been associated with two serious diseases of swine, post-weaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS). During 2002, several outbreaks of clinical disease in pigs with weights ranging from 10 to 70 kg occurred on four farms in different locations in Croatia. The signs were consistent with PMWS and PDNS. Apart from progressive weight loss, pneumonia and/or diarrhoea, multifocal erythematous skin lesions and dermal necrosis were also observed. The PCR results obtained from PCV2 specific oligonucleotide primers confirmed a PCV2 infection. In addition, archive samples that were classical swine fever virus positive and derived from domestic pigs during an outbreak in 1997 were included in this study and one out of the three isolates was found to be positive for PCV2. For a better epizootiological understanding, genetic typing of representative isolates was carried out and compared with available isolates reported in the GenBank databases.     

广西猪繁殖与呼吸综合征病毒感染状况调查

采用RT-PCR技术,对2004年1月至2005年4月期间,广西13个市104个疑似猪繁殖与呼吸综合征病毒(PRRSV)感染猪场,无菌采取231头病、死猪的组织病料(肺脏、淋巴结、脾脏)进行了病毒检测。同时,对鉴定为PRRSV阳性的组织病料和猪场进行了猪圆环病毒2型(PCV2)、猪瘟病毒(CSFV)和猪伪狂犬病毒(PRV)的检测,以确定猪群中PRRSV与PCV2、CSFV和PRV混合感染情况。结果从12个市的115份组织病料中检出PRRSV,病料的平均阳性率为49.78%(115/231),猪场的平均阳性率为61.54%(64/104),不同地市有一定的差异。PRRSV与PCV2、CSFV和/或PRV二重或多重混和感染的组织病料总数为53份,猪场总数为39个,混合感染的组织病料和猪场的总阳性率分别为22.94%(53/231)和37.50%(39/104)。混合感染的组织病料占PRRSV阳性组织病料的46.09%(53/115),混合感染的猪场占PRRSV阳性猪场的60.94%(39/64)。其中以PCV2和PRRSV混合感染的组织病料和猪场数最多。由此可见,PRRSV感染在广西猪场已普遍存在,与其他病毒混合感染现象逐渐趋向复杂化。     

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.     

安徽省部分猪场猪圆环病毒2型感染情况调查

本研究应用PCR技术对采集自安徽省3个猪场(FH、CX、SC)30头发病仔猪的脾、肺、肾、淋巴结共计120份样品,进行猪圆环病毒2型(PCV2)感染情况调查。结果显示,FH猪场PCV2感染率最高达70%,SC和CX两个猪场均为20%;脾、淋巴结PCV2的检出率与肺、肾之间差异显著。表明安徽省猪场的猪群中普遍存在PCV2的感染,且有的猪场PCV2感染的现象相当严重;进一步研究表明PCV2主要感染部位为脾和淋巴结。