THE LESIONAL CHANGES AND PATHOGENESIS IN THE KIDNEY IN AFRICAN SWINE FEVER

African swine fever is a viral haemorrhagic disease of pigs which has been used as a model for the study of viral haemorrhagic diseases in m an. The acute course of the disease is characterized by acute prolifer ative glomerulonephritis, with viral replication in mesangial cells an d occasional focal necrosis of the renal tubular system; hyperplasia o f the collecting ducts is associated with evident virus replication. H aemorrhages have been attributed to endothelial dysfunction, aggravate d by virus replication in endothelial cells in the final stages of the disease. The renal interstitium displays intense oedema and an infilt rate largely composed of macrophages. Virus replication has also been observed in fibroblasts and in the smooth-muscle cells of arterioles a nd venules. In subacute-chronic forms of the disease, various types of glomerulonephritis are observed, ranging from mesangial proliferative glomerulonephritis to focal and segmental hyalinosis associated with immune-mediated phenomena. No striking changes are reported in the ren al tubular system. Interstitial haemorrhages are associated with diape desis due to immunologically mediated events. The interstitium has als o been found to contain a lymphohistiocytic infiltrate with abundant p lasma cells. No evidence has been reported of viral replication in any cell population.