Enzootic pneumonia associated to bovine respiratory syncytial virus (BRSV) in calves in Uruguay

Abstract

An outbreak of pneumonia associated with bovine respiratory syncytial virus occurred in July 2012 in a calf-rearing farm in Flores County is described. Morbidity and mortality were 6.71% and 6.57% respectively. Main clinical symptoms were cough, dyspnea, tachypnea, nasal and ocular discharge and fever. Necropsy was performed in two animals which died from respiratory failure. Gross findings in both were antero-ventral consolidation of lungs with caudo-dorsal emphysema and edema. Histopathological study showed bronchointersticial pneumonia, necrotizing bronchiolitis and exudative alveolitis with syncytial cells in lungs. Lung sections, fixed in formalin, were analyzed by immunohistochemistry. Using this technique it was found positive labeling with anti-BRSV in bronchiolar epithelial cells and syncytial cells, confirming the presence of virus-associated pneumonia lesions.