绿壳蛋鸡青年鸡疑似心包积液——肝炎综合征的实验室诊断

2017年,在河北省涿鹿县某山间林下饲养的60～80日龄绿壳蛋鸡青年鸡突然发生大量死亡,根据其临床症状以及剖检变化初步怀疑为心包积液——肝炎综合征（hvdroericardium hepatitis syndrome,HHS）。为了进一步确诊,选择发病死亡典型病例采集样品进行细菌和病毒的分离、培养、鉴定,以及10周龄SPF鸡致病试验。结果表明,分离到3株大肠杆菌,但接种SPF鸡未出现典型临床症状和发病死亡;利用电镜观察到直径为60～80nm的圆形病毒,该病毒能够凝集大鼠红细胞;病毒分离株引起SPF鸡出现典型的心包积液一肝炎的剖检变化;经琼脂扩散试验鉴定该病毒为禽Ⅰ群腺病毒4型。

Laboratory Diagnosis of a Suspected Case of Hydropericardium Hepatitis Syndrome of Young Blue-shell Chickens

In 2017, a mass mortality of the 60- to 80-day-old young blue-shell chickens freely raised in a forest of a mountain region in Zhuolu County of Hebei Province was observed. According to the clinical symptoms and pathological-anatomical changes, the disease was preliminary diagnosed as suspected hydropericardium-hepatitis syndrome （HHS）. In order to perform the confirmative diagnosis, the clinical samples were recovered from the diseased and dead chickens with typical clinical symptoms and were used for the isolation, cultivation and identification of bacterial and viral pathogens. Furthermore, the virulence of the isolates was assessed in 10-week-old SPF chickens. While three isolates of Escherichia coli were obtained, no typical clinical symptoms and death were observed in the challenged SPF chickens with the isolated strains. Round virus particles with diameters of 60-80 nm were observed by electron microscope; the erythrocyte agglutination test result demonstrated that the viral isolate was able to agglutinate the rat red cells; the SPF chickens challenged with the viral isolate expressed typical pathological-anatomical changes of HHS; the causative agent was identified as adenovirus type 4 by agar diffusion test.