Aspergillosis

What is Aspergillosis?

Aspergillosis is a disease of the respiratory tract and is caused by the fungus Aspergillosis. This fungus can be present anywhere but grows best in moist, warm environments. Malnutrition, especially vitamin A deficiency, is a common predisposing factor.

How is it transmitted?

Aspergillosis can produce many spores which can then become airborne and be inhaled. Moldy food, wet bedding, and unhygienic conditions are breeding grounds for the fungus. If your bird is eating moldy food or in these kinds of conditions, they can easily inhale the spores and become infected with the disease. Small numbers of spores can be tolerated by the body, but large numbers can cause disease. Five million inhaled spores have been found to be necessary to produce fatal infections in day-old chicks and at least 17 million are necessary for an adult bird to become infected. Periods of physiological stress, such as during mating and egg laying, poor nutrition, unsanitary conditions, and prolonged use of certain medications, such as antibiotics or corticosteroids, can make the bird more susceptible to infection.

What are the signs?

Aspergillosis can be very hard to diagnose because its signs are similar to other diseases. There can either be acute or chronic cases of this disease. Birds with an acute case of aspergillosis can have severe difficulty breathing, loss of appetite, frequent drinking and urination, cyanosis (a bluish coloration of mucous membranes and/or skin), and sudden death. 

Chronic aspergillosis, which is more common, is also more deadly because the symptoms don’t show until the disease has progressed extensively. The respiratory system is the primary area of infection and white nodules appear and erode through the tissue. The spores enter the blood stream and travel throughout the body, infecting multiple organs such as the kidneys, skin, muscle, liver, eyes, gastrointestinal tract, and brain. The fungus can affect the trachea, syrinx (voice box), air sacs, and lungs as well. If the lungs are directly involved, the bird will have difficulty breathing or exhibit exercise intolerance. The bird may have a change in voice, reluctance to talk, or a “click” if its syrinx is involved.

Depending on the organs involved, other signs will vary including an uneven gait, seizures, green discoloration of urates, and an enlarged liver. Unfortunately the signs are similar to many other diseases in birds, and since Aspergillosis isn’t very common, it sometimes isn’t diagnosed until necropsy.

How can you treat it?

If diagnosed, surgery can be performed to remove lesions or antifungal drugs can be used. It will be beneficial to keep your bird warm, possibly tube feed him, or give him oxygen. Amphotericin B is used as a fungicidal agent, and with the addition or use of other drugs, can be beneficial. Treatments have improved over the years, but there are usually underlying problems that predisposed the bird to get this disease. This could be chronic vitamin A deficiency or a previous infection that caused scarring and thickening of air sacs which provides an environment for reinfection.

How is it prevented?

Prevention through cleanliness and fresh food is key. Keeping your bird in a well ventilated area and making sure his cage is clean will keep fungus from growing and help keep your bird healthy. Change cage papers daily, deep clean, and disinfect your bird’s cage at least once a month. Give him fresh food and water daily as well. It also helps if you only give your bird the amount of food he will eat in one day. This will alleviate the chance of the old food getting moldy and lessen the risk of your bird eating or breathing in mold.