Malignant catarrhal fever caused 100% mortality in American bison herds in South Dakota. This viral disease presented with severe clinical signs and widespread necrotizing vasculitis in affected animals.
Area of Science:
Veterinary Pathology
Infectious Diseases
Wildlife Health
Background:
Malignant catarrhal fever (MCF) is a severe, often fatal, lymphoproliferative disease.
American bison (Bison bison) are susceptible to MCF, posing a threat to conservation efforts.
Purpose of the Study:
To document the diagnosis and pathological findings of malignant catarrhal fever in American bison.
To characterize the clinical and necropsy findings associated with MCF outbreaks in bison herds.
Main Methods:
Diagnosis based on clinical signs, herd epidemiology, and post-mortem examinations.
Histopathological examination of tissues to identify characteristic lesions.
Main Results:
MCF diagnosed in 3 American bison herds in South Dakota (1973-1976).
Clinical signs included depression, oculonasal discharge, conjunctivitis, keratitis, and diarrhea.
Necropsy revealed ulcerative lesions in the alimentary tract, trachea, and bronchi.
Microscopic findings showed necrotizing vasculitis without thrombosis in multiple organs.
Conclusions:
MCF caused 100% mortality in affected bison herds.
The disease presents with severe gastrointestinal and respiratory lesions and systemic vasculitis.
MCF represents a significant disease risk for American bison populations.