伪狂犬病弱毒株的分离鉴定及生物学特性的研究

在流行病学调查中分离到1株病毒，经鉴定为伪狂犬病弱毒株，定名为F971株。分离病毒经克隆纯化后测得其毒价为10^7.59TCID50/ml，通过细胞中和试验表明分离病毒能也有效地被猪伪狂犬病毒闽A株阳性血清中和。病毒在电镜下可以清楚地观察到囊膜及外周纤突。分离株对3日龄乳鼠有一定的致病力，但对家兔、3日龄乳猪及妊娠母猪都有很高的安全性。用不同的剂量10^0、10^-1、10^-2肌肉注射3日龄乳猪后14天用10^5.7TCID50伪狂犬病强毒攻击，所有试验仔猪均得到保护。用分离株免疫母猪，其后代可获高滴度的母源抗体，15日龄的仔猪能抵御10^5.7TCID50强毒的攻击。用ELISA普查试剂盒测定免疫猪抗体，结果均为阳性，而用g^1-ELISA试剂盒测定抗体时，结果均为阴性。证明分离株具有缺损g^1糖蛋白的特性。综合上述特性，确定F971为1株g^1糖蛋白缺损的猪伪狂犬病弱毒株。

Isolation Identification and Biological Characteristics of an Attenuated Strain of Pseudorabies Virus

A virus isolate designated F971 was isolated from pigs in Shanghai.The virus isolate was purified by plaque technique on CEF monolayer and the titer was 10 7.59 TCID 50 /ml.Virus Neutralization (VN)test showed that the isolate could be neutralized by PRV positive serum.Envelope and peplomers were observed on the surface of the virus under electron microscope.The virus isolate was pathogenic to 3 day mice and safe to rabbits and neonatal pigs.The neonatal pigs inoculated different doses(10 0 ,10 -1 ,10 -2 )of the isolate showed no clinical signs after challenged with a virulent strain of PRV 14 days postvaccination. Weaned pigs acquired high titer maternal antibodies from vaccinated sows and could be protected against PRV infection.Antibody to the isolate was detected from the vaccinated pigs with PRV antibody test kit(for screening),but not detected with PRV g I antibody test kit.According to the above results,it was suggested that the virus isolate was an attenuated PR virus with g I deletion.