Study On Infecting Method And Pathological Observation Of Serositis In Duck

Study on Infecting Method and Pathological Observationof Serositis in DuckThe duck infectious serositis, nowadays newly appears one, is extremely harm to young ducks. Ducks of various ages are proved to be infected through many kinds of paths. But in experimental infection, if the infectious path is different the incidence of disease is very different and the symptoms are not consistent. For the purpose of investigating the best experimental infection method, the clinic signs and the pathological changes, an experimental infection on ducks has been done with the intention for further study.Pasteurella antipestifer was isolated from natural ill cases of a duck farm in Zhang Jiajie By the biochemical identification, the results were as follow: the ferment of glucose, maltose saccharose and lactose were negative, Indole and catalase were negative either, but glutin liquefied was positive. The serological assay by the method of agar immunodiffusion showed that this bacterium was Pasteurellaanatipestifer of serum type I indeed as well.sixty ducks of 12 days old would be infected with Pasteurella anatipestifer by 4pathes which were the trachea, abdominal cavity , crop and foot web. The best path is foot web. On the basis of the experiment of bacteria dose of infection, the most suitable experimental infectious dose of bacteria was 0.10~0.15ml (3 X 108cfu/ml)According to studying the clinic signs and pathological changes of serositis in 30 ducks. The main signs include diarrhea, breathe with difficulty, head tremble and the movement beyond coordination. The pathological changes showed fibrinous pericarditi hepatic degeneration and necrosis, fibrinous serositis, serous-fibrinous pneumonia, nonsuppurative encephalitis and or so. On pathological observation in brain, there were congestion, hemorrhage, leukocytes infiltration , neurons shrinkage and neurons degeneration. Therefore, it can be inferred that the nerve symptom is the inevitable result of brain damage, and brain damage is an embodiment of nervecells malfunction.