牛病毒性腹泻 (1).ppt

1、1,牛病毒性腹泻Bovine Viral Diarrhea(BVD),2,韩 特 博 士,Prepared by:Dr.Terry Hunt BSc.DVM MRCVSDairy Herd Health SpecialistChina Canada Animal Health Initiative,3,病因/发病机理 Cause&Pathogenesis,披膜病毒科（瘟病毒属）Toga virus(pestivirus)通过带毒动物、病畜及污染物质（粪便、唾液、精液、子宫排泄物、流产的胎儿和胎盘）直接接触传播 Transmitted by direct contact with carrier

2、 or sick animals and contaminated materials(feces,saliva,semen,uterine discharge,aborted fetus&placenta)免疫抑制病毒，使动物易感染其它疾病Virus is immunosuppressive and predisposes animal to other diseases病毒可通过胎盘 Virus crosses the placenta,4,病因/发病机理 Cause&Pathogenesis,多系统病毒病Multisystem viral disease古典/胃肠型Classical/G

3、astrointestinal Form呼吸型Respiratory Form生殖型Reproductive Form病毒性腹泻/粘膜病（BVD/MD型）BVD/MD Form,5,危险因素 Risk Factors,未免疫的动物Non-vaccinated animals应激Stress,6,临床症状 Clinical Signs,典型胃肠型 Classical Gastrointestinal Form突发性腹泻Explosive diarrhea反应迟钝，精神萎靡，厌食Dull,depressed and anorexia双相热Biphasic fever口腔有糜烂斑舌头、口腔粘膜Ora

4、l lesions tongue,mucosa of mouth免疫抑制容易发生继发感染Immunosuppressive predisposed to secondary infections大多数在10天后康复 Most recover in 10 days,7,临床症状 Clinical Signs,呼吸型 Respiratory Form持续间歇热Continuous to intermittent fever心率加快，但肺音正常Increased hear rate but normal lung sounds如果无继发感染，大多数在10天后康复Most recover in 10

5、days if no secondary infection,8,生殖型经胎盘感染 Reproductive Form Transplacental infection,第一个三个月1st trimester 流产Abortion第二个三个月2nd trimester木乃伊胎儿Mummified fetus先天性畸形小脑发育不全，眼缺陷，牛犊弱小 Congenital abnormalities cerebellar hypoplasia,ocular defects,weak small calves持续性感染小牛犊 Persistently infected calves第三个三个月3rd

6、 trimester正常牛犊有BVD效价Normal calf with a titre to BVD,9,BVD/MD型BVD/MD Form,感染了细胞病和无细胞病的生物型Infection with cytopathic&non-cytopathic biotypes100%死亡率，但发病率低100%mortality but low morbidity最初经胎盘感染胎儿Were originally infected as fetus-transplacental许多临床动物在624月龄Most clinical animals are between 6 and 24 months

7、of age口腔和鼻腔线形糜烂Oral&nasal linear erosions,10,BVD/MD型BVD/MD Form,食欲废绝和恶病质Total anorexia and cachexia持续性脱水、腹泻Persistent watery diarrhea鼻腔和眼有粘液脓性排出物Mucopurulent nasal&ocular discharge如果存活时间足够长，可能跛行May be lame if they live long enough,11,诊断 Diagnosis,根据型Depends on form临床症状Clinical signs双份血清中和试验Paired se

8、rum neutralization病毒分离Virus isolation,12,鉴别诊断Differential Diagnosis,腹泻和糜烂性疾病Diarrhea&erosive diseases沙门氏菌病Salmonella冬季痢疾Winter dysentery蓝舌病Blue tongue口蹄疫Foot&Mouth Disease牛恶性卡他热MCF牛瘟Rinderpest水疱性口炎Vesicular stomatitis丘疹性口炎Papular stomatitis其它原因的流产Other causes of abortion,13,实验室和病理学诊断 Laboratory and

9、Pathology,组织学淋巴组织坏死Peyers斑Histology necrosis of lymphoid tissue Peyers patches白细胞减少Leucopoenia,14,治疗 Treatment,补液纠正脱水Fluids for dehydration预防性抗生素Prophylactic Antibiotics仔细护理Good nursing care,15,预后情况 Prognosis,警惕临床病例Guarded for clinical cases流产牛Aborting cows will breed backBVD/MD型预后不良 BVD/MD grave pr

10、ognosis,16,后遗症Sequelae,免疫抑制，因此增加了继发感染的易感性Immuno-suppressive so increased susceptibility to secondary infections持续感染的带毒动物 Persistently infected carrier animals,17,预防 Prevention,鉴定和挑选持续感染动物Identify persistently infected animals and cull免疫程序Vaccination program MLV（修饰的活病毒疫苗）MLV用于未怀孕牛Use in non-pregnant cattle每年加强免疫Yearly booster弱毒疫苗（死苗）Attenuated vaccine(killed)怀孕牛用安全，但免疫期短 Safe in pregnant animals but short duration of immunity,