Lung And Airway Disorders Of Pet Birds - MSD Veterinary Manual

Aspergillosis is the most common fungal infection in birds. It occurs in 2 forms. The first form primarily occurs in young birds and newly imported birds and is the result of exposure to a large number of spores of the Aspergillus fungus. The second, more chronic form is more likely to occur in older birds that have been in captivity. Contaminated food, water, and nesting material with poor ventilation are sources of concentrated spores. Aspergillus spores are also widespread in the environment. Birds that inhale the spores may carry them into their lungs and air sacs. When the bird becomes weakened or stressed, and its immune function is decreased, the disease is triggered. Aspergillosis has been diagnosed in many species of birds. Longterm malnutrition, especially vitamin A deficiency, is the most common cause of a weakened respiratory system defense that predisposes birds to the chronic form of aspergillosis.

Aspergillosis usually affects the lower respiratory tract. Although the lungs and air sacs are usually involved, the trachea, syrinx (voice organ), and bronchi may be affected as well. Infection can spread from the respiratory tract to other organs (bone, liver, kidneys, or brain). Eye and skin infections can also occur.

Signs of infection in the severe, short-term form that affects young and newly imported birds include loss of appetite and labored breathing. Sudden death may occur. White mucous congestion of the lungs and air sacs, and nodules in the lungs may be noted during examination of the bird. The air sacs may become inflamed, leading to a condition sometimes called airsacculitis.

In the chronic form, labored breathing, voice change, lack of energy, depression, and emaciation may occur. Infection of the respiratory tract can be severe before signs are noted. Extensive or chronic fungal infection may lead to bone changes and permanent malformation of the upper respiratory architecture. If the central nervous system is affected, the bird may have a lack of coordination and paralysis.

The symptoms caused by aspergillosis are similar to those seen with other respiratory infections. Treatment with antifungal drugs is often successful if the infection is caught in its early stages. It is important to check with your veterinarian whenever your bird has signs of a respiratory illness.

To help prevent aspergillosis, good hygiene, including proper ventilation of the cage or aviary area and proper nutrition, should be maintained at all times.