摘要
本文报道了接种Ⅱ系弱毒疫苗的13个雏鸡群爆发新城疫的临诊和病理观察及实验诊断结果。疫病始发于接种疫苗后1～10d。特征症状是:急性型为吸气性呼吸困难和腹泻,慢性型为神经症状;死亡率高于90%。病理特征如下:a.几乎无出血性素质以及上消化道坏死:b.腺胃和肠道出血性溃疡发生率低。不及15%;c.肠道尤其小肠绒毛上皮细胞和肾小管上皮细胞普遍性坏死。表现为细胞的核固缩和核碎裂。非化脓性脑炎是常见的诊断性病变。此次疫病爆发似乎与按种Ⅱ系疫苗无直接相关,因为显然在接种Ⅱ系疫苗诱导产生出坚强免疫力之前大多数鸡群已受到了强毒新城疫病毒感染;另方面,因考虑到死亡率高,也不排除与该Ⅱ系疫苗免疫原性较低和/或母源抗体干扰相关。
A break of Newcastle Disease(ND) in thirteen flocks of chicks va-ccinated with strain Ⅱ attenuated virus was studied. The disease initialy occursfrom 1 to 10 days after vaccinating. The characteristic signs included inspi-ratory dyspnea and diarrhea in acute type and neural symptom in chronic type.The mortality is higher than 90%. The pathological characteristics are as fol-lows: a. almost complete absence of hemorrhagic diathesis as well as necrosisof the upper alimentary tract; b. low frequency of hemorrhagic ulcer in theglandular stomach and the intestine (less than 15%); c. widespread necrosis ofepithelial cells in the intestine, especially in the small intestine and the renaltubules, in karyopicnosis and karyorrhexis of the cells. Moreover, nonsuppurative encephalitis is a common diagnostic lesion. The authors suggest that the break of the disease does not appear to be di-rectly related to inoculation with strain Ⅱ vaccine, because obviously most ofthe flocks was already infected by the virulent ND virus before the Vaccinationcould induce strong immunity; on the other hand, in consideration of the highmortality the relationship of the break to lower immunogenicity of the strainⅡ vaccine and/or interference of the maternal antibody can not be excluded.
