加拿大奶牛肉牛肺部蠕蟲感染

1、肺部蠕蟲感染Lung Worm Infestation 蟲原性肺炎 (Verminous Pneumonia)Prepared by: Dr. Terry Hunt Translated by Dr. Ren Xiaoling病因/發(fā)病機理 Cause & Pathogenesis· 胎生網(wǎng)尾線蟲Dictyocaulus viviparus· 在夏末和秋天可見Seen in late summer and fall· 急性肺炎和繼發(fā)性細(xì)菌肺炎Acute interstitial pneumonia and secondary bacterial pneum

2、onia· 肺泡內(nèi)可見幼蟲-阻礙空氣進(jìn)出··· Larvae in alveoli of lung block small airways危險因素Risk Factors· 污染的牧草Contaminated pastures· 下雨和灌溉頻率高High rainfall or irrigation· 過度放牧Over stocking on pasture· 引進(jìn)病菌攜帶者Introduction of carrier animals臨床癥狀Clinical Findings急性Acute Disease

3、3; 7-12天前有放牧史History of pasture change 7-12 days ago· 突然發(fā)作、腹部淺式呼吸Sudden onset, shallow abdominal breathing· 咳嗽、呼吸頻率加快Coughing and increased respiratory rate· 體溫升高Elevated temperature· 感染牛警覺，但進(jìn)食Affected cattle may be bright and alert and still eat· 肺部聽診Auscultation - wheezes

4、and crackles over lung fields· 病程迅速：張口呼吸、蒼白、死亡Rapid progression to open mouth breathing, cyanosis and death亞急性Sub Acute Clinical Findings· 咳嗽增加Frequent coughing· 撕裂音擴展到背部Crackling over dorsal lungs· 體重?fù)p失大Severe weight loss· 繼發(fā)細(xì)菌感染Secondary bacterial pneumonia診斷Diagnosis·

5、; 臨床癥狀Clinical signs· 糞便中有幼蟲Larvae in feces· 尸體解剖Post mortem 鑒別診斷Differential Diagnosis· 間質(zhì)性肺炎Interstitial Pneumonia· 支氣管肺炎Bronchopneumonia· 寄生蟲生活史Life cycle of Parasite成蟲寄生氣管內(nèi)，蟲卵經(jīng)咳嗽、吞咽，進(jìn)入腸道發(fā)育Mature worms in bronchi coughed up, swallowed and mature· 排出的胎生幼蟲經(jīng)幾天后才發(fā)育到感染性階段

6、Larvae passed in feces and mature to infective stage (3 plus days minimum)· 度冬的幼蟲在春天有易感性Larvae can over winter and be infective in spring· 感染性幼蟲經(jīng)吞食后3-7周內(nèi)移行到腸壁、淋巴結(jié)、淋巴系統(tǒng)，最終到肺發(fā)育為成蟲和產(chǎn)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實驗室和病理學(xué)診斷Laboratory and Pathology· 貝氏曼沉淀技術(shù)-糞便中的幼蟲Baerman sedimentation technique larvae in feces急性 Acute· 腫大、濕性肺氣腫Enlarged, wet lungs with emphysema· 肺周圍淋巴結(jié)腫大Enlarged regional lymph nodes亞急性 Sub-acute· 成蟲寄生氣管內(nèi)Adult worms in bronchi· 彌漫、間質(zhì)性肺炎Gross

8、 interstitial pneumonia· 繼發(fā)細(xì)菌感染Secondary bacterial pneumonia治療Treatment· 依維菌素Ivermectin 0.2 mg/kg SQ· 其它抗蠕蟲藥Other anthelmintics· 治療繼發(fā)性細(xì)菌感染Treat secondary bacterial pneumonia預(yù)后情況Prognosis· Guarded后遺癥Sequelae· 繼發(fā)細(xì)菌感染Secondary bacterial pneumonia· 肺膿腫Lung abscesses· 充血性心力衰竭Congestive Heart Failure預(yù)防Prevention & Control· 降低牧場污染度Reduce contamination of pasture· 避免青年畜在青綠、潮濕地區(qū)吃草A