1株禽4型腺病毒JS株的分离鉴定

Isolation and identification of a fowl adenovirus 4 JS strain

自2015年以来,心包积液-肝炎综合征在我国部分地区暴发并造成大量肉鸡死亡,从而给养殖户带来巨大的经济损失。2017年从江苏省某发病鸡场的患鸡肝组织中分离获得了1株禽腺病毒4型(fowl adenovirus 4,FAdV-4),将其命名为JS株。Hexon基因同源进化分析显示,该病毒株为我国近期流行株。为了验证该病毒株对鸡的致病性,将10^6.0TCID50的病毒用肌肉注射或口服的方式感染3周龄SPF鸡,连续观察14 d。结果发现:肌注组鸡在攻毒后24 h有精神沉郁的症状,在攻毒后第2~3天大批量死亡,死亡率达90%;而口服组鸡一直没有观察到明显的精神症状且死亡率为0。病死鸡剖检可见心包积液、肝脏肿大发黄、肾脏肿大出血、脾肿大等明显病变;荧光定量PCR检测结果显示,病毒在鸡体内多个组织器官均有分布。结果表明本研究分离获得了1株对鸡有较强致病性的FAdV-4毒株,为有效防控心包积液-肝炎综合征奠定基础。

Since 2015,the hydropericardium hepatitis syndrome(HHS)has broken out in our country and caused the death of many broiler chickens,leading to huge economic losses to farmers.We have isolated a fowl adenovirus 4(FAdV-4)from the livers of the infected birds exhibiting clinical signs of HHS in Jiangsu Province,which was named the JS strain.The homology evolution analysis of the Hexon gene showed that the virus was a recent epidemic strain in China.In order to verify the pathogenicity of the virus in chickens,we administered 10^6.0TCID50 of the virus to 3-week-old SPF chickens by intramuscular injection or oral intake,and observed them for 14 days.The results showed that the chickens had symptoms of depression within the 24 hours after the challenge,and most of them died on the second and third days at a mortality rate of 90%after challenge in the intramuscular injection group;but the chickens in the oral group did not present obvious mental symptoms and the mortality was 0.Obvious symptoms such as hydropericardium,yellowing and swelling of the liver and kidney,and splenomegaly were showed in the dead chickens.The real-time quantitative PCR showed that the virus distributed in many tissues and organs of the chickens.The above results indicated that we had isolated a highly pathogenic FAdV-4,which laid the foundation for further effective control of FAdV-4.