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1、Respiratory Disease Mycoplasma hyopneumoniae 呼吸系统疾病猪肺炎支原体Bob Morrison DVM, MBA, PhD Swine Group University of Minnesota 明尼苏达大学Mycoplasma hyopneumoniae 猪肺炎支原体nTransmission is primarily by direct contact with carrier swine.传播的主要途径是与病原携带猪的直接接触。nAirborne transmission possible 经呼吸道传播使感染成为可能nAny age pig i
2、s susceptible to infection.所有日龄的猪都易感。nMaintained in herds by sow (primarily parity 1,2) to suckling pig contact.在猪群中通过母猪(主要是第一、二产次母猪)与哺乳仔猪接触导致其持续存在。nPrimary clinical problem is in growing pigs, 3 to 6 months old 主要临床问题出现在3到6月龄的生长猪群身上Mycoplasma hyopneumoniae 猪肺炎支原体nLong incubation period 10 to 16 wee
3、ks 长潜伏期10-16周nSlow spread 缓慢传播nLarge numbers present in the early stages of disease大量的病例出现于疾病的早期阶段。nDisease onset is gradual coughing for weeks to months 疾病的发病是渐进性的咳嗽可持续数周到数月nDisease course is markedly affected by concurrent or secondary infections 疾病的进程明显受并发或继发感染的影响nHigh variation in virulence 病原毒力
4、差异很大What does M.hyopneumoniae do? 猪肺炎支原体有什么影响?nColonizes tracheal epithelium 病原定居于气管上皮细胞nDestroys cilia in tracheobronchi, interferes with clearance mechanisms 摧毁气管、支气管上皮的纤毛,干扰气管的清除机制nInterferes with macrophage activity 干扰了巨噬细胞活性nMononuclear peribronchial infiltration 单核细胞在支气管周围浸润nProduces lesions o
5、f pneumonia 造成肺炎的病变nMay be severe in susceptible animals 对易感动物可能有严重后果nProduces slight ADG 导致猪平均日增重的轻微下降nAllows bacterial superinfections -Pasteurella, Strep, Actinobacillus易发生细菌的双重感染巴氏杆菌、链球菌、放线菌Immunohistochemical stain 免疫组化染色Diagnosis 诊断nGross lesions in lungs 肺部的眼观病变well-demarcated, anteroventral,
6、 especially early in disease (7- 28 days) 界线分明、前腹叶、特别是在病变早期nHistopathology 组织病理学Specific and recognizable lesions 特异性和可辨识的病变Distinguish from SIV 与猪流感相区别nDetection of organism by PCR, frozen section FA, immunohistochemistry, culture通过聚合酶链式反应检测病原、冰冻切片的荧光抗体检测、免疫 组织化学、病原培养nSerology 血清学MhypHistopathology
7、 组织病理学Diagnosis 诊断nCulture is difficult 培养困难Fastidious, contamination by other Mycoplasma sp.对培养要求苛刻,易受其他支原体的污染High sensitivity in the early stages of disease 在疾病的早期阶段有高灵 敏度Organism numbers decline over the course of the disease病原数量在整个疾病过程中都在逐步下降nPCR nested vs non-nested 聚合酶链式反应套式与非套式Routine, rapid
8、常规、快速(检验)Tracheobronchial swabs or lung lavage 支气管沾取物或肺部灌洗物nNot upper respiratory tract, nasal swabs less sensitive 不要用上呼吸道采样,鼻拭出物敏感性较差Positive results correlated with 阳性结果与以下因素有关nPresence of clinical signs, lung lesions, eventual seroconversion临床特征的存在、肺部病变、最终的血清学变化 Immunoflurescence免疫荧光 Diagnosis 诊
9、断nSerology is a measure of response to natural infection or vaccination血清学检验结果是衡量机体对自然感染 或疫苗免疫应答的标准Mycoplasma hyopneumoniae Serology 猪肺炎支原体的血清学nSerum antibody 血清抗体Delayed and variable seroconversion, 2 to 8 wks post-infection延迟和产生血清学变化,感染后2到8周 nELISA 酶联免疫吸附Tween 20 ELISA 吐温20酶联免疫吸附nWhole cell membra
10、ne protein antigen 全细胞膜表面蛋白抗原nCross-reactions with non-pathogenic M. flocculare与无致病性的絮状支原体有交叉反应nAntibodies peak 5-7 weeks post infection. Seropositive 1 year later (25% at 8-12 months) 抗体高峰出现在感染后5-7周,1年后仍呈血清学阳性(有25保持8-12个月)DAKO ELISA DAKO酶联免疫吸附nMonoclonal antibody, species-specific epitope 74 kD pro
11、tein antigen支原体抗体,种属特异性的长度为74kD的单抗原决定簇蛋白抗原 nHigher specificity 高度特异性Both have unexpected/false positive results 都有出现非预期/假阳性结果的可能nRepeated serological tests, clinical signs, lesions at necropsy or slaughter.重复血清学检验、临床症状、剖检或屠宰中发现的病变 Evaluating prevalence 流行状况的评估nSlaughter checks 屠宰检查check approximatel
12、y 30 pigs 检查约30头猪as near as possible to 180 days 尽可能接近180日龄的猪at approximately same age 在日龄基本相近的猪身上nCough index 咳嗽的观察observe 2 pens or 40 pigs 观察两栏或40头猪observe for 5 minutes 观察5分钟always same time of day 总在一天的同一时间观察count coughs/minute 记算每分钟咳嗽次数recognize that cough indicates onset of pneumonia, not inf
13、ection and that cough does not give etiologic differentiation辨别咳嗽是肺炎初起的反应、非感染性咳嗽和无法给出病原的咳嗽间的区别nBacterium profile 细菌学剖面Use PCR from nasal swabs 用聚合酶链式反应分辩鼻拭出物的细菌Recognize that positive pigs may not be sick or infectious 要认识到阳性猪可能并没有该病或被感染Respiratory Disease Complex 呼吸系统病的复合感染nM hyo 肺炎支原体plus commonly
14、 detected bacteria其他通常检出菌 nP. multocida, H parasuis, S suis, Actinomyces, etc. 多杀性巴氏杆菌、嗜血杆菌、链球菌、放线杆菌等plus commonly detected viruses其他通常检出病毒nPRRS, PCV-2, Influenza, PRCV, etc.蓝耳病、猪圆环病毒型、流感、伪狂犬病毒等Lung from a pig with porcine respiratory disease complex due to PRRSV, M. hyo., and P. multocida 由蓝耳病病毒、肺炎
15、支原体和多杀性巴 氏杆菌导致的猪呼吸道病复合感染猪的 肺部Respiratory Disease Complex 呼吸系统病的复合感染nEssentially a delayed presentation of mycoplasma必然推迟支原体的疾病表现nUsually seen in late finishing stages通常出现在育成猪阶段的后期nThis complicated form is more severe than uncomplicated enzootic pneumonia有复合感染的情形远较非复合性感染的地方性流行性肺炎nTreatment and contro
16、l are difficult 治疗和控制都很困难Vaccinate sows 疫苗免疫母猪Vaccinate pigs for M hyo 肺炎支原体疫苗免疫猪Gilt acclimation, ensure that gilts have high immunity and low shedding后备母猪的环境适应,确保后备母猪有高免疫力和低散毒率。Serology 血清学nSerology is a measure of immune response either natural or vaccine induced. It does not predict protective effects.血清学检验结果是衡量免疫应答的标准不