One hundred and sixty eight different wild birds (wild chickens, turkeys, ducks, geese, guinea fowls, pea fowls, pheasants, greater flamingo and wild pigeons), of different ages were used in this work to study of the pathological changes in digestive orgaThe most prominent clinical signs among the wild birds were emaciation and diarrhea. The feathers were ruffied and soiled around the vent. The mucous membranes were pale. The heavy infestated birds usually died. The histopathological lesions which occurreinfestation in wild birds (guinea fowls, chickens, pea fowls, pheasants,mallard ducks, green winged teal ducks, grey Chinese geese, greater flamingo and turkeys) were similar. The intestine showed hyperplasia andmetaplasia of the epithelial covering of the intesintal villi. Some casesshowed sloughing of the intestinal villi and necrosis of the intestinal glands with congested blood vessels and leucocytic round cell and eosinophilinfiltration. Some cases showed catarrhal enteritis, in mild infestationNecrotic enteritis and hemorrhagic enteritis with the presence of theparasites inside the intestinal lumen were encountered in case of heavyinfestation. The liver showed aggregations of eosinophils and round cells. to the high economical losses caused by the virulent virus in duckfarms. To fulfill this goal the study included the following:1- Attenuation of The virulent DP virus by two ways.A) Attenuation of the virulent DP virus by passing it on VEROcell culture upto the 8th passage.Titration of all individual passages of OP virus on VERO cellswas done, titer was 10s TCIOsolml at the 1 st passage thenincreased gradually till reached to it’s peak at the 8th passage (1 asTCIDsolml). Study of the growth curve of DP virus on VERO cells showedthat the best time for harvesting the virus was 30 hours PI.The protective dose fifty was 1 029S TCIOso/dose.