Pleuropneumonia, referred to often as shipping fever, is a condition which commonly occurs in performance horses which frequently travel long distance in a horse trailer. The majority of pleuropneumonia cases are caused by a bacterial infection, but can also result from viral agents, mycotic agents, pulmonary hydatidosis, or a complication of septic thrombophlebitis.

Potential complications that have occurred in horses following shipping fever are pneumothorax, pulmonary abscess formation, bronochopleural fistula, cranial mediastinal abscess, restrictive pericarditis, colic, antibiotic-associated colitis, laminitis, and jugular vein thrombosis.