19 isolates were obtained from chicken farms with immune failure in different area.All the isolates were identified as Haemophilus paragallinarum with artificial infection and PCR.

• 摘要从不同地区免疫失败鸡场的鸡传染性鼻炎疑似鸡体内共分离到19株细菌，经回归试验、PCR等方法鉴定为副鸡嗜血杆菌。