鸡胚中新城疫强毒的分离、鉴定与生物学特性研究

将来自有产蛋下降表现的一个肉用型父母代种鸡群的种蛋在实验室内孵化,每日观察鸡胚死亡情况。在孵化的24个鸡胚中有2个在孵化后8~9 d死亡,尿囊液有血凝性。在HI试验中,NDV单因子血清呈现26的HI滴度,对H9和H5亚型AIV单因子血清不呈血凝抑制活性,由此确定为新城疫病毒(Newcastle disease virus,NDV),分别命名为Tengz060104和Tengz060107。对该2个NDV分离株的生物学毒力指标进行测定,Tengz060104株的MDTI、CPI和IVPI分别为56.4 h、1.88和2.67,Tengz060107株的MDTI、CPI和IVPI分别为40.8 h、1.88和2.79。在6周龄SPF鸡攻毒后产生典型的ND症状的病变。表明来自鸡胚的2个分离株属强毒力、速发型NDV毒株。交叉HI中Tengz060104和Tengz060107相互间的同源性为100%,而与经典NDV毒株F48E8的同源性比较分别是66.7%和57.7%。从鸡胚中分离到新城疫强毒株在国内尚未见报道。

Biological Identification of Newcastle Disease Viruses Isolated from Eggs of a Parent Breeder Farm

Among 24 eggs from a meat-type parent breeder chicken flocks with egg-dropping,2 embryos were dead at 8-9 d after incubation.The allantoic fluid from them demonstrated hemagglutination activity.By hemagglutination inhibition(HI) and viral neutralization test in cell culture with mono-antiserum against Newcastle disease virus(NDV),H5-and H9-avian influenza virus(AIV),the agent for HA activity in allantoic fluid of dead embryos were identified as NDV and designated as strains Tengz060104 and Tengz060107.The MDT,ICPI and IVPI for Tentz060104 were 56.4 h,1.88 and 2.67 respectively,and they were 40.8 h,1.88 and 2.79 for Tengz060107.Both two isolated strains can cause symptoms and lesions typical to Newcastle disease in 6 weeks old SPF chickens.The results indicated that two NDV isolates were velogenic virulent strains.In cross HI,Tengz060104 and tengz060107 had 100% homology,but they have only 66.7% and 57.7% antigenic homology with F48E8 strain.This is the first report of isolation of virulent NDV from eggs in China.