Characterization of lesions caused by a South American virulent isolate ('Quillota') of the hog cholera virus

In this study, macroscopic and histopathological lesions produced by a viru lent South American isolate ('Quillota') of hog cholera virus were studied. The virus was inoculated in doses of 10(5)TCID(50) in each of 35 pigs of 2 0 kg live weight. The animals were slaughtered from 4 to 18 days post-inocu lation The presence of virus antigens in lymphatic tissue was confirmed by both direct immunofluorescence and Avidin-Biotin-Peroxidase techniques in f ormalin-embedded tissue samples. Histological sections were stained with ha ematoxylin-eosin and Mallory's phosphotungstic acid haematoxylin methods. T he 'Quillota' isolate used in this study caused a disease characterized by vascular lesions (splenic infarcts, haemorrhages in the lymph nodes and the urinary system and disseminated microthrombosis), and necrosis of lymphocy tes, particularly in the B-areas of the lymphoid organs, lesions that are c haracteristic of the acute form of the disease. Other lesions observed were a non-purulent meningoencephalitis, the necrosis of the epithelial cells o f tonsils, the presence of fibrin nets in the red pulp and a marked thicken ing of the alveolar septa.