Pathological Changes And Viral Distribution In Vivo Of Ducks Infected With H5N1 Avian Influenza Virus

Avian influenza is an infection and/or disease syndrome caused by type A in fluenza virus. People usually think that all of influenza virus could be seperated from waterfowl which is natural host of influenza virus,and the virus have no pathogenicity for waterfowl. But as the pathogenicity and the waterfowl susceptibility of AIV are increased,the role of waterfowl plays on AI occurrence has substantial changed.AIV not only can cause severe pathological injuries in waterfowl,but also can lead to death of the waterfowl,and cause seriously loss of economy in poultry industry.Combining with domestic and foreign reseaches on AI,it mainly centralized at studing on the poultry infected with AIV,such as epidemiological investingation,pathogen isolation and identification,especially on the part of cloning of the virus gene,specific diagnosis of AIV,vaccine development and so on.The distribution in vivo of AlV,the changes and mechanism of pathological especially the ultrastructural changes of ducks infected with AIV have not been comprehensively and systenatically reported.In this study the modem molecular biology techniques and traditional pathological methods were used to detected and observe the dynamic distribution of AIV histopathological and ultrastructural pathological changes.Base on the distribution og the virus in ducks infected with AIV detected at molecular level,the changes and mechanism of organs and tissues injuries of ducks with AIV were studied systematically cellular level and subcellular level.The results showed that:1.The virus were discovered in the heart, liver,digestive tract, respiratory tract in the ducks infected with AIV.It indicated that AIV had the ability of replicative in vivo of the waterfowl,and had extensive tissue tropism.But the emergence time or the duration was different obviously. The AIV existed longest in the liver and pancreas compare with other organs.It indicated the liver and pancreas could be the major target organs.2.Though the gross observation,all kind of organs and tissues of the duck infected with AIV were injured.But in different organs and tissues the degree of pathological injuries were different.The injury of digestive system and immune system were especially obvious.3.The main characteristics of the histopathological changes in ducks infected with AIV were hyperaemia, hemorrhage, degeneration and necrosis. The degeneration and necrosis of lymphocyte in immune organ were obvious at initial period,which lead to the immune function decreased.And organs and tissues injured under the immunosuppressive condition.This may be the mian reason of leading death of ducks infected with AIV at initial period.4.It show obviously ultrastructural pathologic changes in ducks infected with AIV.The chromatin scatter and gather;cell nucleus fragmentation and dissolution ,the mitochondriales cristas present dissolution and vacuolization.In the histiocyte virus-like particle were found.It is thus clear that parenchymal cellular injury is obvious. It indicated that parenchymal cell was the major target cell.It provid for further the experimental basis for the pathogenic mechanism of ducks infected with AIV.