Duck colibacillosis is an acute septic infectious disease caused by Escherichia coli, so it is also called duck colibacillosis. Escherichia coli is widely distributed in nature, and ducks of all ages are susceptible to infection, especially ducklings, with an incidence rate of 70%~90%. It often happens when the sanitary conditions of duck farms are poor, the ground is wet, the indoor ventilation is poor, the smell of ammonia is strong, and the feeding density is too high. The main sources of infection of the disease are sick birds and infected birds, such as their carcasses and feces, contaminated feed, drinking water, ponds, farms, tools and eggs. Healthy ducks are infected with Escherichia coli through the digestive tract or respiratory tract, but they may not get sick immediately. When the body's resistance drops or they suffer from other diseases, the bacteria in the alien body will take the opportunity to enter the blood vessels and distribute all over the body with the blood flow, causing sepsis or other diseases. It can also enter the blood through skin wounds, causing sepsis. In addition, blood-sucking insects and surface parasites in duck houses can also cause the disease.