加拿大奶牛肉牛肺部蠕虫感染

1、肺部蠕虫感染Lung Worm Infestation 虫原性肺炎 (Verminous Pneumonia)Prepared by: Dr. Terry Hunt Translated by Dr. Ren Xiaoling病因/发病机理 Cause & Pathogenesis· 胎生网尾线虫Dictyocaulus viviparus· 在夏末和秋天可见Seen in late summer and fall· 急性肺炎和继发性细菌肺炎Acute interstitial pneumonia and secondary bacterial pneum

2、onia· 肺泡内可见幼虫-阻碍空气进出··· Larvae in alveoli of lung block small airways危险因素Risk Factors· 污染的牧草Contaminated pastures· 下雨和灌溉频率高High rainfall or irrigation· 过度放牧Over stocking on pasture· 引进病菌携带者Introduction of carrier animals临床症状Clinical Findings急性Acute Disease

3、3; 7-12天前有放牧史History of pasture change 7-12 days ago· 突然发作、腹部浅式呼吸Sudden onset, shallow abdominal breathing· 咳嗽、呼吸频率加快Coughing and increased respiratory rate· 体温升高Elevated temperature· 感染牛警觉，但进食Affected cattle may be bright and alert and still eat· 肺部听诊Auscultation - wheezes

4、and crackles over lung fields· 病程迅速：张口呼吸、苍白、死亡Rapid progression to open mouth breathing, cyanosis and death亚急性Sub Acute Clinical Findings· 咳嗽增加Frequent coughing· 撕裂音扩展到背部Crackling over dorsal lungs· 体重损失大Severe weight loss· 继发细菌感染Secondary bacterial pneumonia诊断Diagnosis·

5、; 临床症状Clinical signs· 粪便中有幼虫Larvae in feces· 尸体解剖Post mortem 鉴别诊断Differential Diagnosis· 间质性肺炎Interstitial Pneumonia· 支气管肺炎Bronchopneumonia· 寄生虫生活史Life cycle of Parasite成虫寄生气管内，虫卵经咳嗽、吞咽，进入肠道发育Mature worms in bronchi coughed up, swallowed and mature· 排出的胎生幼虫经几天后才发育到感染性阶段

6、Larvae passed in feces and mature to infective stage (3 plus days minimum)· 度冬的幼虫在春天有易感性Larvae can over winter and be infective in spring· 感染性幼虫经吞食后3-7周内移行到肠壁、淋巴结、淋巴系统，最终到肺发育为成虫和产卵Infective larvae are ingested, migrate through intestinal wall lymph nodes lymphatic system lungs mature to ad

7、ult and lay eggs in 3-7 weeks实验室和病理学诊断Laboratory and Pathology· 贝氏曼沉淀技术-粪便中的幼虫Baerman sedimentation technique larvae in feces急性 Acute· 肿大、湿性肺气肿Enlarged, wet lungs with emphysema· 肺周围淋巴结肿大Enlarged regional lymph nodes亚急性 Sub-acute· 成虫寄生气管内Adult worms in bronchi· 弥漫、间质性肺炎Gross

8、 interstitial pneumonia· 继发细菌感染Secondary bacterial pneumonia治疗Treatment· 依维菌素Ivermectin 0.2 mg/kg SQ· 其它抗蠕虫药Other anthelmintics· 治疗继发性细菌感染Treat secondary bacterial pneumonia预后情况Prognosis· Guarded后遗症Sequelae· 继发细菌感染Secondary bacterial pneumonia· 肺脓肿Lung abscesses· 充血性心力衰竭Congestive Heart Failure预防Prevention & Control· 降低牧场污染度Reduce contamination of pasture· 避免青年畜在青绿、潮湿地区吃草A