Ⅶ型NDV对鸽子和鸡的致病性差异研究

Differences in pathogenicity of genotypeⅦ Newcastle disease virus to pigeons and chickens

【目的】研究NDV强毒（基因Ⅶ型）对鸽子和SPF鸡的致病性差异。【方法】将试验鸽和SPF鸡随机分为4组,每组10只,给其中2组分别滴鼻和肌肉注射鸭源NDV分离株Duck/China/SD03/2009,攻毒剂量为10^6.2EID50,设空白对照组和同居感染组。攻毒后观察临床症状和剖检变化,并对攻毒后3,5,7,14d动物的血清抗体,喉头、泄殖腔的排毒情况及内脏器官的病毒滴度、抗体效价进行检测。【结果】鸽子感染NDV强毒后呼吸道症状不明显,但脑膜严重出血,腺胃和肠道轻度出血,死亡率为10%~30%;而同期SPF鸡攻毒后表现为急性感染症状,死亡率为100%。鸽子在攻毒后第7天均检出排毒,至14d时均未检出。攻毒后5~14d在所检鸽体内脏器官中均检出病毒,以脑、肺、肠中的病毒含量较高。病毒也可诱导鸽子产生较高水平的血清抗体,至14d时血清抗体HI滴度为512~2 048。【结论】基因Ⅶ型新城疫强毒株Duck/China/SD03/2009对鸽子和鸡的致病性差异明显,与SPF鸡相比,鸽子感染后呼吸道和消化道症状较轻,死亡率也较低,表明基因Ⅶ型NDV强毒株能感染鸽子,但对鸽子的致病性较低。

【Objective】This study aimed to compare the pathogenicity of genotype Ⅶ NDV to pigeon and chickens.【Method】Forty pigeons and forty SPF chickens were divided randomly into four groups,respectively,with 10 in each group.Two groups were infected with NDV strain Duck/China/SD03/2009 with the dose of 10^6.2 EID50.The other groups were blank control group and cohabitation infection group.Clinical signs and gross lesions were observed.Serum antibody virus shedding and virus titer in organs at different times after infection were also detected.【Result】Respiratory symptoms of pigeons inoculated with Duck/China/SD03/2009 strain were not obvious.Dead pigeons were mainly manifested by meningeal hemorrhage,glandular stomach and intestinal mild bleeding with mortality rate of 10%-30%.Chickens experimentally infected characterized by acute symptoms and the mortality rate was 100%.Virus shedding of three pigeon groups was detected at 7dpost infection,but was not detected at 14 d.Virus was detected in organs of dead pigeons at 5,7,and 14 dpost infection,and brain,lung and intestine had higher virus titers than other organs.The virus also induced infected pigeons to generate higher HI serum antibody titers of512-2 048 at 14dpost infection.【Conclusion】The pathogenicity of virulent NDVs of genotypeⅦ strain Duck/China/SD03/2009 to the pigeons and SPF chicken was significantly different.Compared with SPF chickens,infected pigeons manifested lighter respiratory and gastrointestinal symptoms and had a lower mortality rate.It is indicated that the genotypeⅦ NDV can infect pigeons,but the pathogenicity is low.