免疫鸡群感染新城疫强毒后排毒及其HI抗体消长

Immunized Chicken Flocks Infected with Virulent NDV

给两组二次新城疫 (ND)疫苗免疫的鸡群分别于 40日龄、 60日龄经胸肌注射强毒株 F48E8(剂量为 0.25 mL)，观察排毒和其 HI抗体效价。结果表明：鸡在感染强毒后第 2天开始排毒，在第 3～ 6天和第 11～ 14天出现两次排毒高峰，整个排毒过程可达 3周，其中抗体水平较低者排毒时间相对较长，频率较高；强毒感染初期，个体 HI抗体先下降 1～ 3个滴度，然后上升，且感染前低者上升速度较快，幅度亦较大。

A ELISA Kit based on monoclonal antibodies was used to detect the dynamical change of sheding virus in experimental chicken.Flocks infected with virulent. Newcastle disease virus(NDV)and Haemagglutination inhibition(HI)titers of early and after inoculating periods was measured by standard method.The results showed that once chicken flocks infected with virulent NDV could excrete virus after one day of inoculating and ended.in three weeks or so late.Two peaks of virus excretion were about 3～ 6 days and 11～ 14 days post－ infection. The time of excretion virus to the infected with lower HI titers was longer than the higher,and its excretion is more rapidly frequency.The HI titers demonstrated that the trends of fall and rise of HI that were the lower HI titers rose more rapidly than those with higher titers before virulent NDV infection.