Updated: Jan 25
Chronic obstructive pulmonary disease, associated with such management factors as indoor confinement with dust, mold, and poor ventilation, causes debilitation ranging from mild exercise intolerance to incapacitation. Treatment should include the alteration of antihistamines, expectorants, antibacterials ( for secondary bacterial infections ), corticosteroids, and/or bronchodilators. If hay is reintroduced, it should be dunked in water about 10 minutes before feeding.
Parasites causing respiratory signs include the lungworm, carried mainly by donkeys, and migrating Parascaris equorum. Ivermectin can be used to treat either condition, and levamisole at 8mg/kg has been used for migrating ascarids.
Rhodococcus equi infection should always be considered in foals 2-5 months of age with signs of respiratory disease, and blood platelet counts of greater than 800,000 and fibrinogen levels greater than 1.8 mg/dl confirm the diagnosis. The treatment choice is rifampicin plus erythromycin, continuing treatment until fibrinogen levels return to normal.
Important viral diseases include influenza, herpesvirus-1, and -4 infection, and rhinovirus, all of which are treated symptomatically. Signs include fever, cough, and purulent nasal discharge; herpesvirus-1 can also cause abortion and a rare neurologic condition. Equine rhinovirus causes similar signs as influenza and herpesvirus infection. Immunostimulants may be used for refractory infections.