一起牛感染支原体与多杀性巴氏杆菌的诊断与治疗

2022年5月甘肃省某肉牛养殖场的部分犊牛,先后出现以咳嗽、呼吸急促、流鼻涕等为主的呼吸道症状,并陆续出现牛只死亡的情况,现场调查及临床检查后初步怀疑为细菌性病原感染。为进一步确诊病原并对症治疗,现场采集症状明显牛只的鼻拭子,同时对病死牛只进行解剖观察,无菌采集肺组织进行实验室病原检测。使用TaqMan探针荧光定量PCR进行3种(牛支原体、牛多杀性巴氏杆菌及牛溶血性曼氏杆菌)牛呼吸道疾病病原核酸检测。结果显示,病死牛只肺脏病变较为明显,肺尖实质化严重,上端有脂肪样颗粒状病灶;鼻拭子及肺组织呈牛支原体和多杀性巴氏杆菌核酸阳性。结果表明,该牛场本次发病是由于感染了牛支原体和牛多杀性巴氏杆菌引起的。通过采取隔离治疗、紧急免疫、严格消杀等综合性防控措施后,该牛场病情逐步好转并恢复正常生产。     

牛多杀性巴氏杆菌的分离鉴定与药敏试验

本研究为对某牛场患有呼吸系统疫病的病死牛进行病原的分离鉴定,并为发病牛场防控措施的制定提供参考依据,经细菌分离培养、形态学观察、生化试验、致病性试验、PCR检测等鉴定为致病性牛多杀性巴氏杆菌,药敏试验显示该分离菌株对氟苯尼考等4种药物高度敏感。     

一株牛源A型多杀性巴氏杆菌的分离与鉴定

对重庆市某牛场运输后的牛的鼻拭子进行病原分离,对其进行培养形态及染色、动物致病性情况观察及16SrRNA序列分析,初步鉴定为牛多杀性巴氏杆菌(PM)。利用PM种特异性引物及荚膜血清特异性引物进行PCR扩增,均得到目的基因条带。由此确定分离菌株为牛荚膜A型巴氏杆菌。     

犊牛呼吸道合胞体病毒和巴氏杆菌混合感染的调查研究

为了对疑似牛呼吸道合胞体病毒和巴氏杆菌混合感染的犊牛进行病原鉴定,本研究采用常规病毒经细菌分离鉴定和PCR方法分别进行分离与鉴定。结果表明,该病毒株能在BT细胞上增殖并产生特征性合胞体形态的细胞病变;无血凝性和血吸附特性;能被牛呼吸道合胞体病毒(bovine respiratory syncytial virus,BRSV)标准阳性血清中和;分离的病毒经RT-PCR鉴定为牛呼吸道合胞体病毒;根据菌落形态、细菌染色特性及生化特性,鉴定分离的细菌为巴氏杆菌。提示,该牛场为牛呼吸道合胞体病毒和巴氏杆菌混合感染。     

应用聚合酶链反应检测禽多杀性巴氏杆菌的研究

根据基因库中禽巴氏杆菌病原的基因序列（U51470）,设计了一对跨幅为488bp的引物,并用这对引物对11个不同血清型的禽巴氏杆菌标准株、9株地方分离株和5株哺孔动物巴氏杆菌菌株及其它6种禽病病原进行了PCR扩增,结果11个血清型的禽源巴氏杆菌和9株禽巴氏杆菌地方分离株均得到了片段大小与实验设计相一致的PCR扩增产物,而对5个血清型的哺乳动物巴氏杆菌和其它6种禽病病原的扩增结果为阴性。该PCR能检出10pg的禽巴氏杆菌DNA模板。     

牛巴氏杆菌病及其控制

为帮助基层临床牛医和牛场(户)技术人员全面认知和科学控制牛巴氏杆菌病(pasteurellosis bovine),文章理论联系实际、图文并茂,从病原特性、流行特点、临床特征、诊断要点、控制措施等5个方面进行有侧重点的描述,以期对牛病防治实践有一定的指导意义。     

一起牛巴氏杆菌病的细菌分离及药敏试验

本试验通过对发病牛场11头患病牛进行临床症状观察,对1头病死牛进行病理剖检,取喉头组织液进行病原菌的分离培养、涂片镜检、生化特性鉴定试验。结果表明:分离的菌株为多杀性巴氏杆菌,诊断为牛巴氏杆菌病。对分离的菌株进行药敏试验,结果该巴氏杆菌对头孢曲松、头孢唑肟、阿莫西林等高敏,对妥布霉素、红霉素等耐药。     

荚膜D型多杀性巴氏杆菌引起兔化脓性肺炎的诊断及病原生物学特性研究

本研究对河南某兔场发生呼吸道感染病死兔的组织样本进行病原核酸检测、分离鉴定和生物学特性研究.病原核酸荧光定量PCR结果显示,多杀性巴氏杆菌呈现阳性;细菌分离获得多杀性巴氏杆菌,命名为HN0604株;特异性和荚膜血清型PCR鉴定结果显示,该细菌为荚膜D型多杀性巴氏杆菌;将分离株HN0604人工感染兔后,复制出纤维素性化脓...     

高原牦牛巴氏杆菌病的防控

正高原牦牛巴氏杆菌病是由多杀性巴氏杆菌引起的急性、热性的一类传染病,多种动物和人也可感染,又称出血性败血症,简称牛出败。该病曾造成过巨大经济损失。笔者根据临床经验和参考文献对高原牦牛巴氏杆菌病的病原、流行病学、临床症状、病理变化、诊断和防治措施进行简述,以期为牦牛生产技术人员提供参考。一、病原多杀性巴氏杆菌为革兰氏阴性菌,呈短杆状或球杆状,一般单个存在,也有成对或短链样排列。该     

牦牛肺炎病原多杀性巴氏杆菌和殊异支原体的分子鉴定与分析

青海省刚察县某牦牛产业基地牦牛发生咳嗽,鼻孔有分泌物流出,呼吸困难等症状的疾病。为快速确诊发病牛的致病原因,及时防控和治疗,从发病和病死的牦牛中,采集鼻腔拭子和肺脏、胸腔积液,利用PCR方法进行分子鉴定与分析。结果显示:此牛场中引发肺炎的病原是A型多杀性巴氏杆菌和殊异支原体两种病原体混合感染,测序结果显示5个有效样品中鉴定的为完全相同的病原,P.multocida-GC1的Kmt基因与参考序列中国株CP031554/3/2/1同源性在99%以上,M.dispar-GC1与参考序列的16S rRNA基因同源性在97%以上。同时在遗传进化角度再次分析确认了鉴定的P.multocida与中国和俄罗斯的A型多杀性巴氏杆菌聚成一大支;鉴定的M.dispar与殊异支原体聚为一支。结果表明,青海刚察地区牦牛存在感染多杀性巴氏杆菌和殊异支原体的潜在风险,该研究为牦牛呼吸道疾病与肺炎的病原学调查和病原的流行病学调查提供了参考数据。     

一例奶牛发生牛支原体肺炎的诊断

牛支原体是严重影响养牛业发展的重要病原。2008年我们报道牛支原体导致＂肉牛传染性牛支原体肺炎＂以来,主要在肉牛发现该病。本文从临床出现类似症状的运输后发病奶牛采集样本,经细菌培养和支原体培养、特异性PCR扩增和16S rRNA测序等病原学检测证实为牛支原体感染。     

Pathogens at the livestock-wildlife interface in Western Alberta: does transmission route matter?

In southwestern Alberta, interactions between beef cattle and free-ranging elk (Cervus elaphus) may provide opportunities for pathogen transmission. To assess the importance of the transmission route on the potential for interspecies transmission, we conducted a cross-sectional study on four endemic livestock pathogens with three different transmission routes: Bovine Viral Diarrhea Virus and Bovine Herpesvirus 1 (predominantly direct transmission), Mycobacterium avium subsp. paratuberculosis (MAP) (indirect fecal-oral transmission), Neospora caninum (indirect transmission with definitive host). We assessed the occurrence of these pathogens in 28 cow-calf operations exposed or non-exposed to elk, and in 10 elk herds exposed or not to cattle. We characterized the effect of species commingling as a risk factor of pathogen exposure and documented the perceived risk of pathogen transmission at this wildlife-livestock interface in the rural community. Herpesviruses found in elk were elk-specific gamma-herpesviruses unrelated to cattle viruses. Pestivirus exposure in elk could not be ascertained to be of livestock origin. Evidence of MAP circulation was found in both elk and cattle, but there was no statistical effect of the species commingling. Finally, N. caninum was more frequently detected in elk exposed to cattle and this association was still significant after adjustment for herd and sampling year clustering, and individual elk age and sex. Only indirectly transmitted pathogens co-occurred in cattle and elk, indicating the potential importance of the transmission route in assessing the risk of pathogen transmission in multi-species grazing systems.     

Vaccination of cattle with Anaplasma marginale derived from tick cell culture and bovine erythrocytes followed by challenge-exposure with infected ticks

Anaplasmosis, a hemolytic disease of cattle caused by the tick-borne pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae) has been controlled using killed vaccines made with antigen harvested from infected bovine erythrocytes. We recently developed a cell culture system for propagation of A. marginale in a continuous tick cell line. In this study, we performed a cattle trial to compare the bovine response to vaccination with A. marginale harvested from tick cell culture or bovine erythrocytes. All immunized and control cattle were then challenge-exposed by allowing male Dermacentor variabilis infected with A. marginale to feed and transmit the pathogen. Nine yearling cattle (three per group) were used for this study and were immunized with cell culture-derived A. marginale, erythrocyte-derived A. marginale or received adjuvant only to serve as controls. Each vaccine dose contained approximately 2 x 10(10) A. marginale and three immunizations were administered at weeks 1, 4 and 6. At week 8, cattle were challenge-exposed by allowing 60 D. variabilis male that were infected with A. marginale as adults to feed on the cattle. Antibody responses of cattle against major surface proteins (MSP) 1a, 1b and 5, as determined by ELISAs, peaked 2 weeks after the last immunization. Cattle immunized with infected IDE8 cell-derived antigens had a preferential recognition for MSP1b while cattle immunized with erythrocyte-derived antigens had a preferential recognition for MSP1a. Protection efficacy was evaluated using the percent infected erythrocytes (PPE), the packed cell volume (PCV), and the prepatent period. A. marginale-immunized cattle showed lower PPE and higher PCV values when compared to control animals and did not display clinical anaplasmosis. The cell culture-derived A. marginale shows promise for use as antigen in development of a new killed vaccine for anaplasmosis.     

Immunization of cattle with Anaplasma marginale derived from tick cell culture.

Anaplasmosis is a hemolytic disease of cattle caused by the ehrlichial tick-borne pathogen Anaplasma marginale. Killed vaccines used for control of anaplasmosis in the US used antigen harvested from infected bovine erythrocytes which was often contaminated with bovine cells and other pathogens. In this study, we performed an initial cattle trial to test A. marginale harvested from tick cell culture as an immunogen for cattle. Eleven yearling Holstein cattle were immunized with the cell culture-derived A. marginale and 11 cattle were non-immunized contact controls. Each vaccine dose contained approximately 2 x 10(10) A. marginale in an oil-based adjuvant. Two immunizations were administered subcutaneously 4 weeks apart and the cattle were challenge-exposed 10 weeks after the second immunization with A. marginale infected blood. Maximum antibody levels as determined by an A. marginale specific competitive ELISA were observed 2 weeks after the last immunization. Antibody responses against major surface proteins (MSPs) 1a and 1beta1 were also characterized and immunized cattle demonstrated a preferential recognition for MSP1beta1. Cattle immunized with the cell culture-derived A. marginale had a significantly lower percent reduction in the packed cell volume (P<0.05) after challenge exposure as compared with the controls and did not display clinical anaplasmosis. The cell culture-derived A. marginale shows promise for use as antigen in development of a new killed vaccine for anaplasmosis.     

Modelling bovine babesiosis: a tool to simulate scenarios for pathogen spread and to test control measures for the disease

Tick-borne diseases are of increasing concern in many countries, particularly as a consequence of changes in land use and climate. Ticks are vectors of numerous pathogens (viruses, bacteria, protozoa) that can be harmful to humans and animals. In the context of animal health, bovine babesiosis poses a recurrent threat to cattle herds. In this study, we use a modeling approach to investigate the spread of babesiosis and evaluate control measures. A previously developed tick population dynamics model (here, Ixodes ricinus) is coupled with a pathogen spread model (here, the protozoan Babesia divergens), which describes pathogen spread in a dairy herd through the following processes: transmission, acquisition, transovarial transmission, transstadial persistence, and clearance of the pathogen. An assessment of the simulated B. divergens prevalence levels in ticks and cattle in the context of existing knowledge and data suggested that the model provides a realistic representation of pathogen spread. The model was then used to evaluate the influence of host density and the effect of acaricides on B. divergens prevalence in cattle. Increasing deer density results in an increase in prevalence in cattle whereas increasing cattle stocking rate results in a slight decrease. A potential increase in deer density would thus have an amplification effect on disease spread due to the increase in the number of infected ticks. Regular use of acaricides produces a reduction in pathogen prevalence in cattle. This model could be adapted to other tick-borne diseases.     

一例人间炭疽病例的溯源调查及处置

2021年6月20日,陕西省汉中市南郑区农业农村局接到同级卫健部门通报,一名牛羊屠宰人员被确诊患有皮肤炭疽。为查清该病例的病原来源以及病原污染面和畜间发病情况,南郑区动物疾病预防控制中心组织相关专业人员立即对关联的屠宰和养殖环节进行了溯源。综合历史资料、调查结果以及实验室检测结果,认为本次人间炭疽疫情的来源可能为被屠宰的病牛。洪水将过往炭疽病原带出,牛通过采食被污染的水、草感染。因非法屠宰病牛导致出现一定的病原传播。通过采取限制移动、监测、对环境及污染区域严格消毒等措施,经后期检测,证实疫情得到彻底控制。该起疫情警示,要加强牛羊养殖、屠宰从业人员的健康宣传及牛羊屠宰行业的管理,加大对非法屠宰、经营、运输病死畜禽行为的查处力度,以确保牛羊肉消费安全。     

The Corynebacterium pyogenes infection of cattle. 2. Tenacity of Corynebacterium pyogenes]

Some common agents were tested for their effectiveness against Corynebacterium pyogenes. The pathogen proved most susceptable to Wofasteril. All germs were killed within ten minutes by a 0.005% solution. Equally good action was recorded from all the other tested agents as well (lactic acid, Lugol's solution, formalin, cupric sulphate, alcohol, and aethacridine. Other studies were conducted with the view to testing the survival capacity of Corynebacterium pyogenes in different media and storage conditions. The pathogen survived three months in routine media and mastitis secretion at room temperature. Regrowth of 38 in 50 strains took place after nine months of refrigerator storage in slanting blood agar tubes with paraffin plugs. Germs sampled from mastitis secretion and stored in a refrigerator were cultivable even after one year had elapsed. The detectability rate of Corynebacterium pyogenes did not change over months by storage of wound infection material at 12 degrees C below zero. The pathogen remained detectable five days from artificial contamination of cattle skin.     

新疆垦区奶牛乳房炎致病菌的调查

本试验选取新疆垦区七个试验牛场,临床调查和试剂诊断,检测奶牛712头,采集奶牛乳房炎阳性乳样314份。其中,奶牛隐性乳房炎阳性检出率平均为36.3%,临床性奶牛乳房炎为16.7%;采集阳性奶样经试验分离鉴定,革兰氏阳性菌仍是引起奶牛乳房炎的主要致病菌,但金色葡萄球菌已基本取代链球菌成为主要的致病菌,其检出率为78.98%。另外,常见环境性致病菌如沙门氏菌、大肠杆菌已明显减少,检出率仅为21.1%和9.24%。相反,绿脓杆菌和蜡样芽孢杆菌的检出率明显增加,其检出率为5.41%和11.15%,而且绿脓杆菌和隐球菌已经成为引起临床性乳房炎爆发的两种新的病原,其中隐球菌已经成为造成顽固性乳房炎的又一种新型病原。     

内蒙古部分地区规模化牛场常见寄生虫的流行病学调查

为了解内蒙古部分地区规模化牛场牛体寄生虫的感染情况，从2015—2017年，采用饱和盐水漂浮法、离心沉淀法、麦克马斯特氏虫卵计数法、血清学和免疫学等方法，对内蒙古呼和浩特市和锡林郭勒盟等地的牛场进行了流行病学调查。结果显示：所检牛群主要感染的寄生虫为毛圆科线虫和艾美耳球虫；2015年还检出了新孢子虫，个别牧场有肺丝虫检出；未有吸虫、绦虫、血液原虫和毛滴虫检出。在为期3年的调查中，经针对性地治疗，寄生虫的感染率呈显著的下降趋势。这些数据的取得为了解所调查牧场的寄生虫感染状况，并根据调查数据开展相关寄生虫的防治工作提供了重要信息。