Histopathological Changes In DHAV-3 Infected Ducklings

Type A duck viral hepatitis is a infectious diseases, which caused by duck hepatitis A virus and with the rapidly spreading and highly fatal. Duck hepatitis A virus mainly infects ducklings of less four weeks old. This study according to using duck hepatitis A virus type 3 (DHAV-3) to infect three-day-old ducklings with three methods (intramuscular injection,oral and nasal drops). And observing the histopathological changes of the infected ducklings by optical microscope. Obtain the following results:1. Histopathological of ducklings infected DHAV-3 by intramuscular injectionInfected ducklings by intramuscular injection are the first to appeared the obvious pathological changes compared with the other two groups. And the liver is the first to appeared the obvious pathological changes compared with other tissues. Livers: lymphocytes infiltration around the central vein and portal regions, liver cells are swelling and granular degeneration during the early phase of infection. Then liver cells are vacuolar degeneration, local hyperemia or haemorrhage and a few heterophiles infiltration in livers. After that nuclei of liver cells were pyknotic and disappear, hepatocyte-necrosis and bile-ductule-proliferation. Finally the structure of livers is disorder, a large number of liver cells were necrosis, The cytoplasm of liver cells is dissolved and only remain the reticular structure. Spleens:During the early phase of infection, spleens are loosen and edema, a few heterophiles infiltration, white pulps with lymphocytoponia, malpignian corpuscle was unconspicuous. Then the lesion is aggravated, besides, red pulp with hyperemia and the lymphocytes of white pulp are vacuolar degeneration. Finally the structure of livers was disorder, malpignian corpuscles are increscent and the number is increasing, the lymphocytes of white pulp are degeneration and necrosis. Lungs:Issues with hyperaemia, hemorrhage and a few heterophiles infiltration during the course of the disease. Kidneys:At the early stage of infection, glomerulus and mesenchyma of kidney tubules with hyperemia or haemorrhage, epithele of kidney tubules is swelling. And then a few heterophiles infiltration, Epithelium of proximal convoluted tubules is vacuolar degeneration and the nuclei are pyknotic and disappeared. Brains:Issues with gliacytes hyperplasia and vascular engorgement during the course of the disease. Pancreas:At the early stage of infection, acinar cells are swelling and lymphocytic infiltrates around the langerhans. And then acinar cells are vacuolar degeneration and physalides in kytoplasm. Hearts:Issues with local inflammatory cells infiltration and hyperemia or haemorrhage. Thymus glands:Issues with focal hemorrhage and local hyperemia, and a few heterophiles infiltration at the early stage of infection. After that, the structure of thymus corpuscles is disorder, thymocytes and lymphocytes are degeneration and necrosis. Harderian glands:Vessels around acini and catheter are hyperemia, epithelial cells of acini are swelling and hyperplasia during the course of the disease. Bursa of abricius:At the early stage of infection, vessels of laminae propria with hyperemia and reticulocytes of medulla are hyperplasia. Then issue with heterophiles infiltration and lymphocytes are necrosis and reduce, aminae propria is loosen and medulla is expansion. Small intestine:During the course of the disease, membranae propria with hyperemia or hemorrhage and laminae propria with lymphopoiesis.2. Histopathological of ducklings infected DHAV-3 by oralIn general, histopathological changes of ducklings infected DHAV-3 by oral is similar to intramuscular injection group. Just the time of histopathological changes occured is delay about 6h compared with intramuscular injection group.3. Histopathological of ducklings infected DHAV-3 by nasal dropsIn general, histopathological changes of ducklings infected DHAV-3 by nasal drops is also similar to intramuscular injection group, besides the time of histopathological changes is delay about 6h, the histopathological changes of brains are different from the other two groups, meninx is thickened and a large number of inflammatory cells infiltration under the meninx.