Pathohistological studies on ducks infected with NDV of duck origin.

To investigate pathohistological changes in ducks infected by NDV of duck origin,healthy Jianhu ducklings were inoculated subcutaneously with 0.5 mL SPF chicken embryos chorioallantoic fluid infected by NDV(WF00D strain).These ducklings were raised and observed in housing with 25 ℃slaughtered randomly at the 4th,8th,12th,16th and 20th day of post-injection,and the pathological changes were observed by light microscope and transmission electron microscope (TEM) after autopsy.The clinical symptom of ducks was minor despite significant differences in body size and weight.Relatively mild inflammatory edema or hemorrhage was seen in the internal organs.Pathohistological changes showed congestive organ or bleeding,inflammatory cell infiltration,cell particles degeneration.Ultrastructural changes included cell degeneration,focal endochylema necrosis,vacuolization of mitochondria,rough endoplasmic reticulum degranulation.The pathological changes progressed gradually during first 16 days However lesions in thymus,bursa Fabricii,spleen and digestive tube on the 16th and 20th day were reduced.The pathohistological changes then improved gradually in most of the major organs except of the liver,kidney and lung lesions.