The epidemiology, clinical signs, necropsy findings and histopathology of 6 cases of malignant catarrhal fever (MCF) in cattle from five farms located in the states of Mato Grosso do Sul and São Paulo, Brazil are described. The disease occurred in cattle of both sexes, ranging from 4-months to 11 years of age. Morbidity rates were 0.25%-6.6% and lethality was 100%. Clinical courses were acute in six cases (2-3 days) and chronic in one (3 months). Presumptive diagnosis of MCF in the cases in this report were made by clinical signs and necropsy findings and comfirmed by histopathological examination. Clinical signs in acute cases were fever, mucopurulent nasal discharge, corneal opacity, drooling and ulcers in several mucosal surfaces and neurologic disturbances. The chronic case had corneal opacity and neurologic signs. Necropsy findings included hyperemia and diphteric lesions in several epithelial surfaces and histopathology consisted of vasculitis, multifocal disseminated foci of mononuclear cell infiltrate, and necrosis of epithelial surfaces.
malignant catarrhal fever; infectious diseases; pathology; viral diseases; diseases of cattle