PathogenesisThe virus replicates in cells of the mononuclear phgocytic system and reticulo/endothelial cells in the lymphoid tissues and organs of domestic pigs. The virus enters the cells by receptor mediated endocytosis and is released from endocytic vesicles into the cytoplasm by a mechanism which involves fusion of the virus envelope with those of the endocytic vesicles. Widespread cell death caused by apoptosis occurs in both T and B lymphocytes in lymphoid tissues and endothelial cells in arterioles and capillaries. This accounts for the lesions seen in acute disease. Disseminated intravascular coagulation develops during the late phase of acute infections and this may lead to the characteristic haemorrhagic syndrome. |
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