The ICPI in 1-day-old chickens was 1.51,MLD in chicken embryos was 10 -8 ,MDT was 46.2 h,EID 50 in chicken embryos was 10 -10.1 .According to the provided criterion,the results indicated that the avian NDV isolated strain be a virulent strain.

• 该新城疫病毒分离株对 1日龄雏鸡脑内接种致病指数 (ICPI)为 1.；5 1；鸡胚最小致死量 (MLD)为 10 -8；平均死亡时间 (MDT)为 46