A study of outbreak and histopathology of Mycoplasma pneumonia in sheep, in Shahrekord, Iran

An outbreak of mycoplasmal pneumonia occurred in a flock of 180 head of sheep. The prominent clinical signs included pyrexia, coughing, respiratory distress, nasal discharge, ocular opacity in some cases, hot and swollen joints, lameness, and depression. Routine post-mortem examinations were performed on 11 dead sheep. The gross lesions included reddening, consolidation, and localized necrosis in different areas of the lung, the presence of a fibrinopurulent membrane on the pleural surface, and serofibrinous fluid in the thoracic cavity. Culture of the pneumonic lungs, liver, thoracic lymph nodes and nasal swabs in liquid and solid media yielded mycoplasma which was microscopically visible on solid media after 24 h at 37°C. Microscopically, pulmonary lesions consisted of proliferation of collagen connective tissue, in the midst of hyperemia, vasculitis with thrombus formation, and necrotizing fibrinopurulent pneumonia.