腺胃病变型鸡传染性支气管炎病毒的分离鉴定及免疫试验

The Isolation, Identification and Experimental Vaccination of Avian Infectious Bronchitis Virus Causing Proventriculitis

从山东省某鸡场发生的以腺胃肿大为特征病变的病鸡群中分离获得了 1株具有冠状病毒特性的病毒。该分离毒株在电镜下可见到直径为 80～ 14 0 nm、有囊膜及纤突呈冠状排列的病毒粒子。感染鸡胚的尿囊液没有血凝活性 ,经1%胰酶处理后能凝集鸡红细胞 ,其血凝活性可被传染性支气管炎部分毒株的阳性血清所抑制 ;经 SPF鸡胚传代时 ,可使胚胎发生规律性死亡 ,胚体卷缩 ,呈现明显的侏儒胚特征 ;接种于 10日龄 SPF雏鸡 ,从具有相似病变特征的病鸡腺胃组织中可再分离到该病毒。血清中和试验表明 ,部分传染性支气管炎病毒株阳性血清对其具有不同程度的中和作用。据此 ,确定该分离株为可导致鸡腺胃肿大的传染性支气管炎病毒。用具有腺胃肿大病变的病鸡脏器制备的组织灭活疫苗和用传代鸡胚尿囊液制备的油乳剂灭活疫苗 ,可使鸡获得较好的免疫力 。

One local strain (named as D strain) of avian infectious bronchitis virus (IBV), which conduce to the severe swell of proventriculus in the field, was isolated from a chicken farm in Shandong province. Electron microscopic examination substantiated the existence of the virus particles, which cover with an envelope and has characteristic club-shaped projections distributed on its surface. The diameter of the virions is about 80-140 nm. The allantoic fluid of the infected chicken embryo digested by 1% trypsin for 1 hour possesses the hemagglutination activity, while the untreated doesn′t agglutinate the avian erythrocytes. The hemagglutination activity can be inhibited by passive serum produced with some strains of IBV. Embryo mortality and dwarfing increased as the number of serial passages increase. By the 5-6 passage, most of the embryos display the characteristic embryo changes-the embryo curled into a spherical form with the thickened amnion closely adhered to it, stunted, and died. The same virus can be obtained from the 10-day SPF chickens, which represent the severe swell of proventriculus after inoculated with suspension of proventriculus tissue of the sick-died chickens. The isolate can be neutralized respectively by hyperimmune antiserum against some strains of IBV, such as H (52), QX strain, to some extend. The results demonstrate that the present isolate is a new type of IBV which results in a proventriculitis. Based on the isolation and identification, the immunity of the isolate was processed and experimentally inactivated vaccine was prepared. The results showed that sera antibodies against IBV (D strain) were generated in 10 to 14 days post inoculation and it was up to 85% after 21 days. A second inoculation 1 month later needed to achieve a protective rate of 87%-100% within 6 months followed.