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Pneumonia, Pleuropneumonia & Pleuritis, Generally

Synonyms: Shipping Fever, Transit Fever

Pleuropneumonia is a lung infection (pneumonia), combined with an infection of the pleural cavity (pleruitis). It is also called “Shipping Fever” because its development is often associated with the stress of long-distance trailering.

Pleuropneumonia is uncommon in horses but potentially a serious or fatal problem that must be diagnosed and treated early and correctly. It is a bacterial (rarely fungal) infection of the lung that may extend into the space around it (the pleural cavity). Fluid accumulates in this space as part of the inflammatory process (pleural effusion).

Infection can be difficult to control and becomes more difficult the longer that infection persists. In time, fibrin strands and clots (an inflammatory product) fill the space and isolate pockets of fluid. Clearing this fluid is difficult and expensive, and requires the use of thoracic drains and flushing.

Pneumonia may start as respiratory tract infection that progresses deeper into the lungs or may start without an obvious cause. Aspiration pneumonia refers to a situation in which foreign material and bacteria is inhaled or gains access to the lungs.


Catch respiratory disease early before it becomes well established in the pleural space. Ensure good respiratory health by providing good ventilation at all times. Try to decrease the amount of dust and debris during transport, soak hay before putting it in hay nets, and stop often and allow horses to lower their head position.

Helpful Outside ResourcesCredible Equine Health Information on the Internet

Author: Doug Thal DVM Dipl. ABVP


Cha ML, Lais RR, Costa MV: Inhalation Therapy in Horses: In Veterinary Clinics of North America.


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