A strain of virus was isolated from 20 cloacal of ducks in Nanjing using SPF chicken embryos.The virus showed haemagglutination activity but not inhibited by positive sera against New castle disease virus(NDV) and egg-drop syndrome-76 virus(EDSV).HI test indicated that the isolate belonged to H9 subtype of influenza virus.The assay of intravenous pathogenicity showed that the isolate had low pathogenicity to chickens,but no pathogenicity to ducks.The study also indicated that the 5-week-mouses could be infected with morbidity and mortality.

1 发病情况 南通市某肉鸭场于2003年7月份出孵雏鸭5 000余只,采用池边网床饲养.雏鸭16日龄开始发病,并出现死亡.随后2 d内死亡1 300多只.用链霉素、恩诺沙星给鸭饮水,但效果不佳,病情得不到控制.