Equine pleuropneumonia.

Pleuropneumonia is a clinically important equine disease, predisposed by a number of identifiable factors. Successful management is largely dependent on early identification and prompt initiation of appropriate treatment strategies. Rapid resolution of the disease process is associated with appropriate treatment commenced within 48 h of the causative insult. Lower airway contamination by oropharyngeal organisms and subsequent extension into the pulmonary parenchyma results in respiratory dysfunction and systemic toxaemia. Acute disease is associated with the isolation of facultatively anaerobic organisms, especially beta-haemolytic Streptococcus spp. and Pasteurellaceae. Delayed or inappropriate treatment is likely to result in chronic disease characterized by the involvement of anaerobic bacteria and a poor response to therapy. The primary mode of treatment for anaerobic infection of the human thorax is surgical drainage and resection of necrotic tissue but whilst such techniques have been described for the management of equine pleuropneumonia, the size of the equine thoracic cavity hinders accurate diagnostic evaluation and successful completion of such intervention. The chronic nature and cost of ongoing treatment and limitations on choice of antimicrobial agents warrant a poor prognosis for survival and a poorer prognosis for return to athletic endeavour.