幼狐脑炎母源抗体消退情况监测

本研究采用微量中和实验的方法，对30日龄、45日龄、60日龄幼狐的传染性脑炎母源抗体进行检测。结果显示，30日龄幼狐的传染性脑炎母源抗体水平较高，中和抗体平均效价为1：48.3；在45日龄断乳期该母源抗体平均中和抗体效价显著下降到1：18.3；在60日龄该母源抗体基本消失，多数中和抗体效价低于1：2.9。实验结果表明，45-50日龄对幼狐进行传染性脑炎疫苗首免，能避开免疫空白期和母源抗体干扰，获得较好免疫效果。

The decreasing of the maternal antibodies to fox encephalitis in fox cubs

Maternal antibodies against fox encephalitis virus in fox cubs at ages of 30,45 and 60 days were detected by micro neutralization test. The results showed that the level of the maternal antibodies was higher at 30 day-old with an average SN titer of 1：48.3,it was reduced sharply to 1：18.3 at 45 day-old when weaning,and almost disappeared at 60 day-old as most of them were below 1：2.9,suggesting that good immunity could be obtained if the infectious fox encephalitis vaccine was inoculated for the first time between 45 and 50 day-old and the immune gap and the maternal antibody interference could be avoided as well.