Studies on the pathogenesis of bovine petechial fever ('Ondiri disease')

Abstract

An experimental infection of 20 calves resulted in 14 cases of the disease, 6 fatal. Monitoring of pathological changes in the development of the disease and electron microscopy show the first symptoms appearing after 5-9 days' incubation. These are petechiae on the mucous membranes, caused by invasion of the capillary endothelium by rickettsial parasites. Extensive haemorrhage into connective, muscular and epithelial tissues follows. Sections of liver tissue showed granular organisms in the sinusoidal cells.