肉鸡传染性喉气管炎的发生和诊断及其PCR诊断方法的建立

Diagnosis of infectious laryngotracheitis in broilers and establishment of PCR diagnostic methods

传染性喉气管炎(ILT)是家禽重要的呼吸道疾病,主要危害成年鸡和产蛋鸡。但是,自2019年4月以来,在山东省多个地区发生多起商品肉鸡、地方品种肉鸡等感染该病并致病现象。临床主要表现为严重的呼吸困难、喘鸣、打喷嚏和伸颈呼吸,严重的咳出带血的分泌物,呼吸道粘膜出血和充血。经绒毛尿囊膜接种10日龄SPF鸡胚,5 d后可产生典型的绒毛尿囊膜病变。参考GenBank中传染性喉气管炎病毒(ILTV)的序列,设计出一对针对其ICP4基因的特异性引物,对可疑病料和分离出的病原分别进行PCR扩增,结果扩增出目的条带,经测序证实为ILTV。特异性和敏感性试验证实,新建立的PCR可快速、准确地鉴定出病原,具有一定的临床推广应用价值,为有效防控ILT的发生奠定了基础。

Infectious laryngotracheitis(ILT)is an important respiratory disease in poultry,which mainly harms adult chickens and laying hens.However,since April 2019,a number of commercial broilers and local breed broilers have been infected by infectious laryngotracheitis virus in many areas of Shandong Province,and have led to serious outbreaks.The disease is characterized by anorexia,depression,and serve respiratory distress,with coughing,sneezing,gurgling,gasping,and rales.The trachea is often partially occluded,and bloody,mucous exudates may be expelled during violent expectorating efforts.The ILT virus(ILTV)was isolated by inoculation of chorioallantoic membrane(CAM)of 10-day-old developing of SPF chicken embryos.Lesions developed on the 5 days post-infection.Referring to and combining the sequence of infectious laryngotracheitis virus(ILTV)in the GenBank,a pair of specific primers were designed to target its ICP4 genes,and the target bands were PCR amplified for suspicious and isolated pathogens which were confirmed as ILTV by sequencing.The specificity and sensitivity experiments confirmed that the newly established PCR can identify pathogens quickly and accurately,and has certain clinical popularization and application value,which lays a foundation for effective prevention and control of ILT.