仔猪肠道疾病.ppt

Enteric Diseases of Young Pigs 仔猪肠道疾病,作者：Larry Firkins, DVM, MS, MBA College of Veterinary Medicine University of Illinois 美国伊利诺斯大兽医学院,Diarrhea remains one of the leading causes of neonatal mortality in swine 下痢一直是新生仔猪死亡的主要原因,Definition of Diarrhea 下痢的定义,Excess water in feces relative to dry matter.粪中含水量过大 Normally, much of the fluid is absorbed in the small intestine before it exits the ileum 通常，大部分水都在进入回肠之间就在小肠中被吸收了 Colon serves to conserve water and electrolytes结肠只起吸收水和电解质的作用,Mechanisms of Diarrhea下痢的机理,Secretory Diarrhea分泌性下痢 Result of the effect of enterotoxins secreted by bacteria and some viruses细菌和其它病毒分泌的肠毒素造成的结果 Alteration in secretion of electrolytes, water, and bicarbonate: gradient pulls water into lumen电解质、水和碳酸氢钠的分泌发生改变：使水进入肠腔 Absorption continues: Chyle in lymphatics,Mechanisms of Diarrhea下痢的机理,Malabsorptive Diarrhea吸收不良性下痢 Reduction in surface area of intestine 肠粘膜表面积减少 Loss of absorptive capacity吸收能力减弱 Villous atrophy绒毛萎缩 Chyle absent in lymphatics淋巴乳糜缺乏 Undigested ingesta ferments未消化的食糜发酵,Mechanisms of Diarrhea下痢的机理,Effusive Diarrhea渗漏性下痢 Result of severe damage to mucosa粘膜严重受损的结果 Necrotoxins produced by bacteria细菌产生的坏死毒素 Leakage of serum proteins and water due to vascular damage血管受损导致血清蛋白质和水漏出 Loss of absorptive capacity吸收能力减弱,Arriving at a Diagnosis诊断,History病史 Age of onset发病年龄 Vaccination history免疫接种历史 Sudden death vs. protracted diarrhea猝死和长期下痢,Arriving at a Diagnosis诊断,Selection of specimens病料采集 Diarrhea of 24 hrs or less下痢开始后24小时以内 Untreated未经治疗 Avoid pigs which “died during the night”不要从夜间死亡的猪采集病料,Selecting Segments of Intestine 肠段的选择,Histopathology组织病理学 Sections representative of all areas of intestines要选择能代表肠道所有区域的部分 Better to have many small pieces than one large piece最好要采集多个较短肠段，而不要只采集一个很长的肠段 Segments 1 cm long, opened lengthwise根据纵向尺寸的不同，采集1厘米左右的肠段,Fresh samples样本要新鲜 7 10 cm segments of ileum, jejunum710厘米回肠和空肠的肠段 Segment of spiral colon结肠螺旋襻的肠段,Selecting Segments of Intestine 肠段的选择,Causes of pig diarrheas 仔猪肠炎原因,Nursing Weaning 断奶前 断奶后 E. coli 大肠杆菌 11% 49% Rotavirus 轮状病毒 14% 12% C. perfringens 19% 0% 产气荚膜梭状芽孢杆菌 TGE 传染性胃肠炎 8% 7% Coccidiosis 球虫病 20% 15% Source-Iowa State Diagnostic Lab 2000-2002,Colibacillosis - E. coli 大肠杆菌病, 分泌过度性下痢 Hypersecretion diarrhea 12小时至34天龄或更大的猪下痢 Diarrhea from 12 hours to 3-4 days 可能极度水样化 May be extremely watery 随后发病的各窝猪更严重 Increases severity in succeeding litters 头胎仔猪可能更严重 Gilt litters may be more severe,Diagnosis - E. coli 大肠杆菌病诊断, 进行性水样下痢 progressive watery diarrhea 实验室用琼脂平板培养大肠杆菌 culture E. coli on agar plate 用分离的大肠杆菌作敏感性测定 culture and sensitivity testing,Diarrhea Treatments 下痢的治疗,Gentamycin 庆大霉素 Spectinomycin 壮观霉素 Kanamycin 卡哪霉素 Neomycin 新霉素 Sulfa, trimethoprim 磺胺， 三甲氧苄氨嘧啶,Colibacillosis vaccines 大肠杆菌疫苗,菌苗含有最常见的致病性菌株 在母猪产前的5周和 2周注射 此后的母猪只需产前2周注射一次 疫苗应该含有K88, K99, 987P, F41。 Bacterin - most common pathogenic strains Inject sows 5 weeks and 2 weeks prior to farrowing Subsequent farrowings - 2 weeks only,Clostridium perfringens type C C型产气荚膜梭状芽孢杆菌,12 hrs 7 days12小时7天 Death in as little as 4-8 hours48小时内死亡 Bloody or yellow to gray diarrhea带血或黄色至灰色下痢 Necrotoxins坏死毒素,Clostridium perfringens type A A型产气荚膜梭状芽孢杆菌,Watery to pasty, white to yellow diarrhea水样至粘性下痢，白色至黄色 Toxins毒素 -2 often seen in isolates from pigs with diarrhea下痢仔猪分离到的菌株常见-2毒素 Lesions similar to those with type C病变与C型所致的病变相似 Necrosis of tips of villi绒毛顶端坏死 Lack hemorrhage无出血,Prevention and Treatments 预防和治疗,Vaccinate sows 5 and 2 weeks prior to farrowing May require development of an autogenous vaccine分娩前5周和2周对母猪免疫，可能需要生产自家菌苗 Feeding antibiotics such as bacitracin to sows prior to farrowing分娩前对母猪饲喂杆菌肽等抗生素 Treat piglets at birth with penicillin or antiserum在仔猪出生时用青霉素或抗血清对其进行治疗,TGE 传染胃肠炎,Highly contagious viral disease 高度传染性病毒病 Can result in 100% mortality 能引起100%死亡 Survival depends on the age of the pig 存活取决于猪的年龄 Endemic forms can develop 可能成为地方流行性,TGE 传染胃肠炎,Cause is a coronavirus 病原为冠状病毒 Attacks cells lining the small intestine 攻击小肠内壁细胞 Survives for long periods of time in the environment 在环境中可长期存活 Very stable when frozen 冰冻后非常稳定生存,TGE 传染胃肠炎,TGE 传染胃肠炎,Inactivation of the virus 病毒的灭活 sunlight 阳光 drying 干燥 warm temperatures 高温 most disinfectants 多数消毒药,TGE Clinical Signs 传染胃肠炎临床症状,Severe diarrhea 严重的下痢 Vomiting 呕吐 Dehydration 脱水 High mortality in young pigs under 2 weeks of age 两周龄以下的猪死亡率高 Lower mortality in pigs over 3 weeks of age 三周龄以上的猪死亡率低,TGE Spreads Rapidly 传染胃肠炎传播快,Very short incubation period 潜伏期很短 Within 2-3 days majority of pigs on farm can be infected 2-3天内猪场内多数猪即被感染,Sources of Infection 传染胃肠炎传染源,Primarily infected shedding pigs 主要为受感染的排毒猪 People second most important 人是第二重要的传播因素 Starlings and other animals 椋鸟科鸟和其它动物,Diagnosis of TGE 传染胃肠炎诊断,Clinical signs 临床症状 Necropsy 病理剖检 Diagnostic Laboratory 实验室诊断 histological confirmation 病史确认 positive FA test 荧光抗体阳性检测,Treatment of TGE 传染胃肠炎治疗,Keep warm 保暖 Antibiotics to control secondary bacteria 应用抗生素防止继发感染 Wean pigs early 早期断奶 Young pigs rarely survive despite treatment efforts 尽管进行治疗，年龄小的猪仍然很少存活。,TGE Immunization 传染胃肠炎免疫,Deliberate entire herd exposure to virus 故意让整个猪群接触病毒 Timing is important 上述处理的时间很重要 Is infection in farrowing facility? 产房内有无感染? Goal is to shorten the overall effect 目标是减轻整体影响,TGE Immunization 传染胃肠炎免疫,If not in farrowing facility 如果产房内无感染 Isolate these facilities from the rest of the farm 将产房与场内其他猪舍隔离开 Expose other sows on the farm 自然免疫场内的其它母猪,TGE Vaccines 传染胃肠炎疫苗,Injectable 注射型 Oral 口服型 Variable protection to piglets through the colostrum 通过初乳对仔猪提供的免疫力强弱不一,Autogenous TGE Vaccine 传染胃肠炎自家疫苗,Harvest intestines from acutely infected piglets when clinical signs appear 当出现临床症状时，收集急性感染仔猪的小肠 Homogenize in a blender 放在组织粉碎机内制成匀浆 Material can be frozen for later use 冰冻保存备用,Autogenous TGE Vaccine Use 传染胃肠炎自家疫苗的应用,One piglets intestines per 20 sows in 2 1/2 liters of water, 125cc(1/2 cup) per sow mixed in feed 每20头母猪饲喂一头仔猪的肠道组织，肠道组织匀浆溶于2.5升水中；每头母猪125毫升(半杯)混入饲料中。 Feed to sows at least 3 weeks prior to farrowing 至少在分娩前三周投喂母猪 Planned exposure to specific groups may not be contained 可以不包括对特定年龄组猪的计划性感染,Autogenous TGE Vaccine Use 传染胃肠炎自家疫苗的应用,Exposure to entire herd may eliminate the virus from the farm 饲喂整个猪群可能会根除猪场内的病毒 Eliminates carrier pigs 清除带毒猪 Virus dies out 病毒死亡 Best done during hot weather 最好进行于天气炎热时,Enzootic (chronic) TGE 地方性(慢性)传染胃肠炎,Diarrhea in 7-14 day old piglets 714日龄的猪表现腹泻 Post weaning in the nursery 断奶后的保育仔猪 Not all pigs or litters affected 不是所有的猪或窝都被被感染 Vomiting is rare 极少发生呕吐 Sows not sick 母猪不发病,Dealing With Enzootic TGE 对付地方性(慢性)传染性胃肠炎,Entire herd exposure 令整个猪群接触病毒 All-in/All-out production 全进全出的生产系统 Good sanitation and disinfectant 良好的卫生和消毒措施 Footbaths to reduce spread of virus 实施脚浴以减少病毒传播,Rotavirus 轮状病毒,黄色至白色下痢 Yellow to white scours 危害10日龄至3周龄的仔猪 A