SPAOPD (Summer pasture associated obstructive pulmonary disease)
SPAOPD is similar to COPD but occurs in horses on pasture usually in the spring and summer.
The condition is thought to be a hypersensitivity to pollens, moulds or dietary toxins and the allergic reaction to these causes irritation of the airways producing increased mucus secretion and thickening of the airways.
Signs
Affected horses will have a cough, increased respiratory rate (heaves) and a nasal discharge. Occasionally horses may become ill, go off their food and have an increased temperature if a secondary bacterial infection occurs in the inflamed airways.
Diagnosis
Clinical signs of the condition are usually enough to make an initial diagnosis and start treatment, however, in many cases further tools can be used.
Endoscopy can be used to examine the presence of inflammation in the airways and amount of mucus present. A sample of this mucus can be taken, a tracheal wash, and examined to determine the cells and, in some cases, bacteria present. Horses can show allergies to certain pollens.
Treatment
Environmental management is often of little help, however, horses can be moved indoors into dust-free housing. Drugs that can be used to manage the disease include drugs to dilate the airways (e.g. ventipulmin) and anti-inflammatory drugs (e.g. steroids). These are often best delivered directly into the lungs via an inhaler. Antibiotics are used if bacterial infection is suspected. In a case of acute respiratory distress similar agents can be injected to supply a more rapid response.