鲢、鳙鱼暴发性流行病流行面广,发病快、死亡率高。一旦发病损失严重。该病主要发生在夏季,水温在20～30℃时。病鱼体表、头嘴、眼眶充血,同时伴有不同程度的鳃盖下缘、鳍的基部、肠道和内脏充血发炎。有时口腔、肌肉也发炎充血。也有体症不明显而死亡的。防治措施如下: Silver carp, bighead carp outbreak epidemic epidemic wide, fast onset, high mortality. Once the incidence of serious loss. The disease occurs mainly in summer, the water temperature at 20 ~ 30 ℃. Fish body surface, head and mouth, orbital congestion, accompanied by varying degrees of the lower edge of the operculum, the base of the fin, intestinal and visceral hyperemia and inflammation. Sometimes oral cavity, muscle inflammation also congestion. There is no obvious physical illness and death. Prevention and control measures are as follows: