Respiratory diseases are very common in pet birds and can be caused by bacteria, viruses, fungi, or parasites. Recognizing the disease and treating it early greatly improve the chances that your bird will recover.
For avian influenza, see the separate Avian Influenza (Bird Flu) topic.
Aspergillosis
Aspergillosis is the most common fungal infection in birds. It is caused by infection with the Aspergillus fungus, which is commonly found in the environment as microscopic spores.
Aspergillosis has two main forms. The acute form comes on suddenly and occurs mainly in young birds whose immune systems are not yet fully developed or that are exposed to large numbers of spores. The chronic form occurs over time, and mainly in older birds.
Aspergillus spore levels can be high in contaminated food, water, and nesting material, as well as in poorly ventilated areas. Birds inhale the spores into their lungs, and disease develops when the bird is stressed or its immune system is weakened.
Many types of birds can be affected by aspergillosis. Long‑term malnutrition, especially vitamin A deficiency, is a major risk factor for chronic aspergillosis because vitamin A is critical to maintaining the lining of the respiratory system.
Aspergillosis usually involves the lower respiratory system in birds, including lungs, but it can also affect other parts of the respiratory system, including the trachea (main breathing airway), syrinx (voice box), and air sacs (little pouches of air found in the respiratory system). It can also spread to bone, liver, kidneys, brain, eyes, and skin.
In the severe, short‑term form of aspergillosis in young birds, symptoms include poor appetite and difficulty breathing, and sudden death can occur. In the chronic form, symptoms include labored breathing, change in voice, low energy, and severe weight loss.
A bird's respiratory system can be greatly damaged before aspergillosis symptoms are noticed. Extensive or long‑standing fungal infection can cause bone changes and permanent deformities of the respiratory system. If the central nervous system is affected, the bird might also show lack of coordination and paralysis (inability to move).
Because the symptoms of aspergillosis resemble those of other respiratory diseases in birds, evaluation by a veterinarian is essential. Antifungal drugs might help, if treatment begins early. Good hygiene, proper ventilation, and balanced nutrition are key for preventing this disease.
Hypersensitivity Pneumonitis (Macaw Asthma)
Some macaws, especially blue-and-gold macaws, develop a respiratory condition, called hypersensitivity pneumonitis, that is similar to chronic obstructive pulmonary disease (COPD) in people.
Birds that develop hypersensitivity pneumonitis often live in poorly ventilated spaces with cockatoos and African grey parrots, which produce a fine, white, powdery substance (called powder down) from their feathers that, when breathed in, can irritate the airways of sensitive birds. Macaws do not always need to be housed separately from these species, but good air circulation and cleanliness are essential.
Birds with hypersensitivity pneumonitis also commonly develop secondary bacterial or fungal infections. Several tests, including blood counts, x-rays, and microscopic analysis of fluid collected from the trachea (main breathing airway) and lungs, might be required to diagnose the condition. A lung biopsy is needed to confirm the diagnosis.
In an acute breathing crisis, oxygen is the first treatment. Your veterinarian might also give your bird anti‑inflammatory drugs. Long‑term management of the disease requires excellent air quality, ventilation, and the use of good air filters near the cage.
Birds with hypersensitivity pneumonitis might have repeated episodes that require hospitalization. Environmental changes and improved ventilation decrease the risk of severe relapses, but permanent lung scarring and decreased ability to exercise are common. Affected birds might have a shortened lifespan.
Macaws with this condition should be housed away from birds that produce powder down.
Newcastle Disease
Newcastle disease is a viral disease that can affect both pet birds and poultry. It spreads through inhaled respiratory droplets, ingested food or water that is contaminated with bird droppings, direct contact with infected birds, and contact with contaminated objects. In the United States, it is rare in pet birds.
Symptoms of Newcastle disease include poor appetite, weight loss, sneezing, nose or eye discharge, breathing difficulty, bright-yellow‑green diarrhea, loss of coordination, head bobbing, and seizures. Later in the disease, an affected bird might show paralysis (inability to move) of the wings or legs, twisting of the neck, abnormal head positions, and enlarged pupils. Some birds die suddenly without warning signs.
There is no cure for Newcastle disease, and treatment is not recommended. If you see symptoms of this disease in a bird, you should notify your veterinarian immediately. Suspected cases must be reported to state and federal animal health authorities because of the disease’s potential impact on poultry.
There is a vaccination to prevent Newcastle disease, but it is typically used in poultry rather than in pet parrots.
Respiratory Parasites
Air Sac Mites
Air sac mites infect the entire respiratory system of birds, especially canaries and Gouldian finches. Birds with mild cases of air sac mite infection might not show any symptoms. Birds heavily infested with air sac mites might have a hard time breathing, bob their tails up and down as they breathe, make high‑pitched noises and clicking sounds, sneeze, and breathe with an open mouth.
Stress, handling, and exercise worsen symptoms of air sac mite infestations in birds. Heavy infestations can be fatal. Treatment requires antiparasitic drugs given by mouth or injected, along with thorough cage disinfection and elimination of all items (such as wood perches) in which mites can hide.
Gapeworms
Gapeworms live in the wall of the trachea (main breathing airway) of some finches and canaries. Birds infected with gapeworms have trouble breathing and gape (open their mouth wide) for air, giving the parasite its name.
Gapeworms are more common in birds housed outdoors and rare in caged birds, in general, but if present, they can cause death from suffocation or pneumonia. Treatment (removing the worms from the trachea and administering antiparasitic drugs) is effective only if started early.
Sarcocystosis
Sarcocystosis in birds is caused by microscopic protozoa that form cysts in the respiratory system, kidneys, nervous system, and muscles. It is a major cause of death in parrots housed outdoors in the southern United States.
Indoor birds can be infected if their food is contaminated by these protozoa. The life cycle of these parasites involves insects and opossums. Birds become infected by ingesting food contaminated with opossum feces or insects, such as cockroaches, that have had contact with infectious opossum feces.
In areas where the numbers of protozoa that cause sarcocystosis are high, death rates are high in untreated birds such as cockatoos, African grey parrots, Eclectus parrots, and other Eclectus parrots or other parrot species native to Asia, Africa, or Australia that haven't been exposed to these protozoa before.
Symptoms of sarcocystosis include low energy, regurgitation of water, and anemia (low red blood cell count). Treatment includes supportive care—fluids, supplemental feeding, anemia treatment—and long‑term antiprotozoal drugs.
For More Information
Also see professional content regarding aspergillosis, hypersensitivity pneumonitis, and parasitic diseases in pet birds, as well as Newcastle disease and helminthiasis in poultry.
