It appeared isometric with a diameter of 25 nm,had its coat protein with MW 24 700 dalton,contained three double strand RNA species that is 3.8 kb,1.4 kb,1.1 kb respectively.

• 病毒呈二十面体 ,直径约 2 5nm ,有空心和实心 2种粒子 ,具有分子量为 2 4 7kd的外壳蛋白和长度分别为 3 8kb、1 4kb、1 1kb的 3个双链RNA组分。