A Case Report on FMD in a Holstein Friesian Bull: Necropsy and Histopathological Insights

Abstract

Foot-and-mouth disease (FMD) is an economically significant diseases affecting cattle and other ruminants with distinct clinical manifestations and pathophysiological outcomes. In adult cattle, FMD typically presents with mucosal and dermal lesions. In calves, myocarditis is the predominant cause of mortality which is rare in adult cattle. This case report presents an unusual fatal manifestation of FMD with severe myocardial and systemic lesions in a 3-year-old Holstein Friesian Bull from CODEK Farm, Karnaphuli, Chattogram, Bangladesh, which had been treated for Bovine Ephemeral fever (BEF) four months prior to death. The bull exhibited acute anorexia and fever without external skin lesions prior to death. Necropsy revealed notable gross lesions, including ulcerative lesions in the tongue, hemorrhagic and emphysematous lungs, petechial hemorrhages and necrosis in the heart muscle, enlarged friable liver, hemorrhagic mesenteric lymph nodes, and intestines. Histopathological analysis revealed severe myocarditis with coagulative necrosis of myocardial fibers, interstitial infiltration of lymphocytes, plasma cells, and histiocytes, along with a tigroid heart appearance. Liver histology demonstrated fatty degeneration, central vein congestion, hepatic cord disintegration, and neutrophilic infiltration. Lung tissue showed marked congestion, hemorrhage, necrosis of bronchiolar epithelium, and fibrous tissue proliferation. Brain histology revealed lymphocytic meningitis, glial cell proliferation, and neuronal degeneration, while intestinal mucosa displayed hemorrhagic changes and goblet cell proliferation. The presence of myocardial lesions in this adult cow, a feature more commonly associated with FMD in calves, suggests a potential correlation between prior BEF infection and heightened susceptibility to myocardial damage. BEF’s transient immunosuppressive effects might have predisposed the animal to systemic complications during subsequent FMD infection. This case report underscores the importance of considering prior disease history, particularly immunosuppressive conditions like BEF and other related infections, in understanding mortality risks in FMD outbreaks in adult cattle particularly those involving myocardial lesions. Therefore, robust vaccination strategies, and biosecurity measures are recommended to mitigate such outcomes.