宁夏部分地区规模化奶牛场4种疫病的血清学调查分析

为了解宁夏主要奶牛养殖区规模化奶牛场牛传染性鼻气管炎(IBR)、牛病毒性腹泻(BVD)、新孢子虫抗体和布鲁菌病原的流行状况,采用酶联免疫吸附试验(ELISA)对未接种过IBR、BVD、新孢子虫疫苗、接种过布鲁菌疫苗的奶牛群体进行血清抗体检测,并对银川、吴忠和青铜峡地区的阳性状况进行分析。结果发现,76份流产牛血清中,IBR抗体阳性率为50.00%(38/76),BVD抗体阳性率为19.74%(15/76),新孢子虫抗体阳性率为27.63%(21/76),布鲁菌阳性率为19.74%(15/76),4种病原均感染的阳性率为34.21%(26/76),IBR和新孢子虫混合阳性率占总阳性率的34.62%;408份非流产牛血清中,BVD抗体阳性率为12.75%(52/408),IBR抗体阳性率为21.08%(86/408);IBR和BVD在宁夏的3个主要养殖区均有不同程度的流行,其中以银川地区阳性率最高。说明宁夏部分地区IBR和BVD在不同的地区存在着不同程度的感染,流产牛中普遍存在上述4种疫病的感染并且IBR和BVD阳性率明显高于非流产牛。     

宁夏地区奶牛病毒性腹泻及牛传染性鼻气管炎的流行病学调查

为了解宁夏地区奶牛的病毒性腹泻和传染性鼻气管炎的流行情况,本研究对宁夏不同地区的奶牛采取了135份耳组织和376份血清,分别对牛病毒性腹泻病毒抗原及牛传染性鼻气管炎病毒抗体进行了检测。结果显示,牛病毒性腹泻病毒抗原阳性率最高为0.5%,平均阳性率为0.01%;牛传染性鼻气管炎病毒抗体阳性率最高为100%,平均阳性率为85.1%。证实了宁夏地区已经存在着较为严重的牛病毒性腹泻病毒及牛传染性鼻气管炎病毒的感染。牛病毒性腹泻以及牛传染性鼻气管炎的流行病学调查为我区制定出科学有效的综合防控措施及促进地区奶业健康可持续发展提供依据。     

牛病毒性腹泻病毒合并犬新孢子虫感染引起奶牛流产的诊断

针对某牛场奶牛流产率过高的状况,对该牛场流产情况及相关疾病进行诊断调查。该场2007—2009年奶牛年流产率分别为13.89%,16.52%和19.24%,流产率逐年上升。2009年1月至2010年4月的流产病例多发生于头胎牛,流产时妊娠时间以4～6月龄为主。收集流产奶牛病料24份。牛病毒性腹泻病毒血清抗体阳性率75%,犬新孢子虫血清抗体阳性率83.33%,其中9个病例为牛病毒性腹泻病毒与犬新孢子虫混合感染。布氏杆菌、李氏杆菌与牛传染性鼻气管炎病毒检测均为阴性。场内对照牛20头,牛病毒性腹泻血清抗体阳性率5.00%,犬新孢子虫抗体阳性率15.00%,与流产病例检测结果存在显著性差异。由此,可初步确定牛病毒性腹泻病毒合并犬新孢子虫感染是导致该牛场流产的主要原因。     

宁夏地区奶牛场牛传染性鼻气管炎的血清学调查

为了了解牛传染性鼻气管炎(IBR)在宁夏地区成年奶牛群中的流行情况,课题组针对宁夏地区18个规模化奶牛场的成年牛群进行随机采血,共采集470份,通过酶联免疫吸附试验进行牛传染性鼻气管炎的血清学调查。结果显示:存在338头牛传染性鼻气管炎病毒(IBRV)抗体阳性牛,场群阳性率为100%,不同场群之间阳性率存在差异,从13.3%~100%不等,平均阳性率达到71.9%,表明牛传染性鼻气管炎已在宁夏地区广泛流行。此调查结果为宁夏地区奶牛传染性鼻气管炎的流行病学研究提供重要信息,为防控牛传染性鼻气管炎提供科学依据。     

宁夏部分地区肉用母牛流产的病原血清学调查分析

为了调查宁夏地区流产肉用母牛5种流产相关病原的流行情况,通过采集不同地区92份有流产史的基础母牛血清样本,采用酶联免疫吸附试验(ELISA)对5种流产相关病原抗体/抗原进行检测和分析。ELISA检测结果表明,92份样品中,5种病原抗体阳性率为98.91%(91/92),抗体阳性率由高到低分别为牛犬新孢子虫(82.61%)、牛传染性鼻气管炎病毒(69.57%)、衣原体(44.57%)、布鲁氏菌(30.43%);未检出牛病毒性腹泻病毒。混合抗体阳性率中主要以2种病原混合抗体阳性率最高(50.00%),其中牛传染性鼻气管炎病毒和牛犬新孢子虫混合抗体阳性率最高。研究结果表明,宁夏主要肉牛养殖地区均出现不同流产相关病原感染的情况,主要以混合感染为主。在肉用母牛养殖过程中,应加强对以上病原的检疫并采取相应的防控措施。     

蚌埠市某奶牛场IBRV和BVDV的血清学调查

本试验对蚌埠市一家未进行牛传染性鼻气管炎及病毒性腹泻免疫的规模化奶牛场的94份奶牛血清样品,分别使用牛传染性鼻气管炎及病毒性腹泻抗体ELISA试剂盒进行检测,共检出牛传染性鼻气管炎阳性血清65份,阳性检出率为69．15％;病毒性腹泻阳性血清83份,阳性检出率为88．30％。结果表明,该规模化奶牛场存在牛传染性鼻气管炎及病毒性腹泻的感染和接触史,应采取净化措施进行控制。     

河南洛阳地区流产奶牛感染性病原的分子检测

为调查洛阳地区引起奶牛流产的主要病原,于2013年7月至2014年3月,收集该地区6个奶牛场(或小区)共42头新鲜流产胎牛,及其母体的血液、阴道分泌物和鼻腔分泌物,计为42例样本,采用PCR或RT-PCR方法对所采集样本进行新孢子虫、弓形虫、胎儿三毛滴虫、布鲁菌、牛传染性鼻气管炎病毒(IBRV)和牛病毒性腹泻病毒(BVDV)6种常见流产病原的核酸检测。结果显示,被检样本总感染率为42.9%(18/42),其中新孢子虫感染率最高,为40.5%(17/42);:IBRV次之,为11.9%(5/42);胎儿三毛滴虫、布鲁菌、弓形虫和BVDV感染率分别为2.4%、2.4%、2.4%和0。14.3%(6/42)的被检样本存在混合感染,其中以新孢子虫十IBRV混合感染为主(50%,3/6)。结合被检流产奶牛的临床特征及饲养管理等因素,推断新孢子虫是导致该地区奶牛流产的最主要病原,本研究结果将为该地区有效防控奶牛流产提供科学依据。     

奶牛四种流产性疾病的流行现状及疫苗研究进展

奶牛布氏杆菌病、传染性鼻气管炎、病毒性腹泻-黏膜病及新孢子虫病是导致我国奶牛流产发病比例升高的主要疾病,有效防控这四种疾病一直是世界关注的重点之一。本文对上述四种疾病的流行现状及疫苗研究进展进行了综述。     

牛病毒性腹泻病毒抗体胶体金检测试纸条的制备

采用sf9昆虫细胞-杆状病毒系统重组表达牛病毒性腹泻病毒P80蛋白抗原,经纯化鉴定后将P80蛋白用胶体金标记作为示踪抗原,未标记的P80抗原作为捕获抗原,并以羊抗牛IgG抗体作为质控抗体,建立了牛病毒性腹泻病毒抗体快速诊断试纸条。试验结果表明,该试纸条检测灵敏度高,特异性良好,与牛口蹄疫病毒、牛传染性鼻气管炎病毒无交叉反应。使用建立的胶体金试纸条和IDEXX牛病毒性腹泻病毒ELISA抗体检测试剂盒同时检测80头份牛血清,阳性结果符合率为86.7%,阴性结果符合率为100%,总符合率为95%。该试纸条可用于临床牛病毒性腹泻病毒抗体的诊断和检测。     

内蒙古地区部分奶牛场牛传染性鼻气管炎的血清学调查

为了解内蒙古地区牛传染性鼻气管炎在奶牛场的流行情况,对内蒙古地区的16个大、中、小型奶牛养殖场的2 321头奶牛,应用ELISA方法进行牛传染性鼻气管炎的血清流行病学调查。结果显示,5个大型奶牛场牛传染性鼻气管炎的阳性率在68.5%~100%之间,5个中型奶牛场的阳性率在34.0%~84.2%之间,6个小型奶牛场的阳性率在32.6%~89.3%之间,平均阳性率为75.7%。     

当前奶牛重大传染病的现状及思考

本文就近年来奶牛养殖业中高发的牛传染性鼻气管炎、牛病毒性腹泻及布氏杆菌病的流行现状进行分析,并在诊断与综合防控方面提出建议。     

Prevalence of brucellosis and infectious bovine rhinotracheitis in organized dairy farms in India

This study was carried out to investigate the prevalence of bovine brucellosis and infectious bovine rhinotracheitis (IBR) in organized dairy farms with history of abortion in India. ELISA and Rose Bengal Plate Test (RBPT) were used to detect the seropositive animals and the test results indicated that 22.18% and 13.78% animals were declared as sero-positive by ELISA and RBPT, respectively. Milk Ring Test (MRT) was carried out only in one farm and 12.82% of the tested animals were turned positive. Culture examination analysis of milk samples, two animals revealed the presence of organisms indistinguishable from Brucella spp. The organism was confirmed as brucella by morphological characteristics and biochemical tests. An overall sero-prevalence of antibodies against IBR was found to be 60.84%. None of the genital and nasal swab samples was found to be positive for presence of bovine herpesvirus -1 (BHV-1) on repeated passage in Madin-Darby Bovine Kidney (MDBK) cell lines. Brucella and IBR considered as the causal agent for abortions in these farms. The present study indicates the urgent need and the necessity for control of these infectious diseases which cause heavy economic losses to the organized farms.     

A farming systems study of abortion in dairy cattle on the Atherton Tableland: 2. The pattern of infectious diseases

The role of infectious agents on dairy farms on the Atherton Tableland in tropical north Queensland was studied as part of a comprehensive investigation into the causes of bovine abortion. The prevalence of antibody in serums collected from 7 herds whose annual abortion rates ranged from 3% to 21% were as follows: Leptospira hardjo 49.9% (426/853), L. pomona 0.4% (3/851), bovine virus diarrhoea (BVD) 33.7% (35/104). Infectious bovine rhinotracheitis virus (IBR) 11.5% (12/105), Akabane virus 92.2% (95/103), Aino virus 62.1% (64/103), Chlamydia psittaci 3.1% (37/1004), Brucella abortus 0% (0/851), and Toxoplasma gondii 0% (0/105). Testing of serums against a wide range of leptospiral serotypes indicated that reactions occurring in the Hebdomadis and Sejroe serogroups were probably cross reactions with L. hardjo. Infection with L. hardjo and Akabane virus occurred prior to first mating and contact with Aino virus occurred during first pregnancy. Infection with BVD and IBR viruses was sporadic. The pathology and microbiology of 32 aborted foetuses from 24 Tableland herds (10 from the group of 19 farms under more intense study) were performed. Lesions associated with a Sarcocystis-like agent were present in 6, leptospires in 1, suspected toxic hepatosis in 2 and purulent bronchopneumonia (Staphylococcus aureus) in 1 foetus. No diagnoses were made in the remaining 22 foetuses (69%). Evidence for a common infectious cause of abortion in the population was inconclusive.     

A study of some infectious causes of reproductive disorders in cattle owned by resource-poor farmers in Gauteng Province, South Africa

Two hundred and thirty-nine cattle from Gauteng Province in South Africa were tested for various pathogens causing reproductive diseases includingbovine viral diarrhoea/mucosal disease (BVD/MD) virus, infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) virus, Neospora caninum and Brucella abortus usingvarious tests. For BVD/MD virus, 49.37% tested positive, 74.47% for IBR/IPV virus, 8.96% for Neospora caninum and 3.8% for Brucella abortus. The result for Brucella abortus is higher than the national average, possibly due to the small sample size. A high seroprevalence of antibodies to both BVD/MD virus and IBR/IPV virus was evident. These 2 viruses should be considered, in addition to Brucella abortus, when trying to establish causes of abortion in cattle. The clinical significance of Neospora caninum as a cause of abortion in Gauteng needs further investigation. One hundred and forty-three bulls were tested for Campylobacter fetus and Trichomonas fetus, and a low prevalence of 1.4% and 2.1% respectively was found in this study. The clinical implications of these findings are discussed.     

新疆部分规模奶牛场牛病毒性腹泻病的流行情况调查与防控措施

为了解新疆地区部分规模奶牛场牛病毒性腹泻病（BVD）的流行情况,优化防控措施,以达到建设防控净化场的目的,自2020年11月到2021年7月累计采集新疆5 个地区16 个奶牛场共计26 997 份血清、3 843 份犊牛耳组织进行全群普检。通过使用IDEXX公司牛病毒性腹泻病毒（BVDV）抗原检测试剂盒检测及RT-PCR复检结合测序等方法,淘汰阳性牛,同源性分析流行毒株情况。BVDV血清抗原检测结果为：沙湾某奶牛场BVD阳性率为1.63%（38/2 326）;乌鲁木齐某奶牛场BVD阳性率为0.35%（4/1 132）;其余奶牛场均为阴性。犊牛耳组织抗原检测结果为：乌鲁木齐某牛场BVDV阳性率为1.17%（4/342）;其余奶牛场均为阴性。研究结果揭示,奶牛场通过淘汰BVDV阳性牛,调整免疫程序、制定消毒程序等方法,可有效净化BVD。     

BVD approach: vaccination and eradication

The vulnerability of cattle populations that do not have adequate levels of antibodies against the bovine virus diarrhoea (BVD) virus was demonstrated in February 1999, when a contaminated vaccine against infectious bovine rhinotracheitis (IBR) was accidentally used. Only cattle with antibodies against BVD survived this unintentional challenge. A BVD infection can be detected easily with currently available laboratory techniques, but the virus is less easy to eliminate. The risk of financial loss is small, and the costs are limited, if mainly seronegative cattle, selected on the basis of sampling, are given the live vaccine. Over the last 7 years this approach has been applied to about twenty dairy farms. This approach would be compatible with a BVD eradication programme.     

An analysis of an early-warning system to reduce abortions in dairy cattle in Denmark incorporating both financial and epidemiologic aspects

Emergency preparedness relies on the ability to detect patterns in rare incidents in an early stage of an outbreak in order to implement relevant actions. Early warning of an abortion storm as a result of infection with a notifiable disease, e.g. brucellosis, bovine viral diarrhea (BVD) or infectious bovine rhinotracheitis (IBR), is a significant surveillance tool. This study used data from 507 large Danish dairy herds. A modified two-stage method for detecting an unusual increase in the abortion incidence was applied to the data. An alarm was considered true if an abortion were detected in the month following the alarm month, otherwise false. The total number of abortions that could potentially be avoided if effective action were taken ranged from 769 (22.9%) to 10 (0.3%), as the number of abortions required to set the alarm increased from 1 to 6. The vast majority of abortions could, however, not be predicted, much less prevented, given this early-warning system. The false to true alarm ratio was reduced when the number of abortions that set the alarm increased. The financial scenarios evaluated demonstrated that the value of an abortion, the cost of responding to an alarm and the efficiency of the actions are important for decision making when reporting an alarm. The presented model can readily be extended to other disease problems and multiple-time periods.     

新疆某规模化奶牛场牛传染性鼻气管炎病毒抗体水平检测

为了调查新疆地区某规模化奶牛场牛传染性鼻气管炎（IBR）发病情况,通过采集不同生长阶段牛群血清共计362 份,使用牛传染性鼻气管炎病毒gB（IBR-gB）抗体检测试剂盒检测牛传染性鼻气管炎病毒（IBRV）抗体效价,评估该奶牛场IBRV疫苗免疫效果。结果显示,后备牛中犊牛和青年牛IBRV抗体阳性率分别为88.57%（31/35）、75.00%（21/28）;成年母牛中泌乳期母牛、干奶期母牛IBRV抗体阳性率分别为81.46%（145/178）、95.04%（115/121）。阴性数共44 份,可疑数8 份,IBRV抗体平均阳性率为88.38%;结果表明,疫苗接种后,不同生产阶段牛群均可产生不错的抗体保护效果,为奶牛场防控IBR提供依据。     

北京地区规模化奶牛场牛病毒性腹泻病血清学调查

对北京郊区6个未进行牛病毒性腹泻病（BVD）免疫牛场的546份奶牛血清样品,使用牛病毒性腹泻抗体ELISA试剂盒进行检测,并对其中3个牛群进行牛病毒性腹泻病毒（BVDV）血清抗原筛查。共检出阳性血清514份,总阳性率94.1%,其中5个牛场的场内血清抗体阳性率在95%以上。牛病毒性腹泻持续性感染牛（PI牛）筛查的3个牛群均有阳性牛检出。结果表明,北京地区规模化奶牛场存在牛病毒性腹泻感染和接触史,应采取净化措施进行控制。