新城疫单抗ELISA试剂盒监测免疫鸡群中新城疫强毒

应用新城疫（ND）单抗ELISA试剂盒对2个免疫鸡群中ND强毒感染情况及个体感染强毒后排毒动态跟踪监测，并平等测定其HI抗体效价。共采集泄殖腔棉拭子和血液对应样品2317份。结果表明：HI效价2－14之间的个体均可检出强毒，其中HI效价在6以下和11以上的个体强毒检出率都较高。HI效价在6以上的个体仍角感染强毒，强毒感染导致HI抗体水平上升，且感染前低者上升速度较快，幅度亦较大；并且发现排毒个体的高水平抗体是强毒感染所致。个体感染强毒后排毒过程可长达3周，而且感染前抗体水平低者排毒时间相对较长。强毒一旦侵入鸡群便可在群内巡回传播，长期维持下来。

Application of Monoclonal Antibody Based on ELISA Kit for Detection of VirulentNewcastle Disease Virus Infection in Vaccinated Chicken Flock

The ELISA kit based on Monoclonal Antibodies(MABs)for rapid diagnosis of Newcastle disease virus(NDV)was applied to detect virulent NDV in cloacal swab specimens from the vaccinated chicken flock in continuous surveillance for a long time.Haemagglutination inhibition(HI)was parallelly measured.A total of 2317 matched specimens of cloacal swab and blood were taken from two vaccinated chicken flocks.The result in this experiment showed that viral antigen might be detected in cloacal swabs of the chickens with HI titers between 2 to 14.The infection rate of virulent NDV was higher between 2_6 and 11_14 than those between 6 to 10.Those chickens with titers of HI above 6 can still be infected with virulent NDV.The result demonstrated the trend of fall and rise of HI was that the lower were rose more rapidly than the higher before virulent NDV infection.It showed that the high HI titers of infected chickens was caused by virulent NDV infection.In general,the infected individual excreted virus for 3 weeks or so.Once virulent NDV invaded a chicken flock,the susceptible individual in the flock would become infected,then the virus was excreted from the infected and cycled within the flock coninuously.