ALLERGIC ALVEOLITIS

Copyright © 1989 By Dave McCluggage, DVM
Written for NCS

The Bird Hospital
Boulder, Colorado
(All Rights Reserved)

Copyright Notice & Disclaimer Statement

Allergic Alveolitis is a respiratory hypersensitivity reaction (allergic reaction) to repeated inhalation of organic particles. Synonyms include extrinsic allergic alveolitis, budgerigar dander pneumonicosis, bird breeder's disease, allergic interstitial pneumonitis and pigeon breeder's lung. Allergic alveolitis is called a zoonotic disease, since people acquire the disease from animals (psittacosis is another zoonotic disease). In fact, it is one of the most important zoonotic diseases because it is relatively common and it can be life threatening. The frequency in man is hard to assess because many people test positive yet show no clinical symptoms. Studies in Great Britain indicate an incidence of 8% in budgie owners. In other words, 8 out of every 100 people that own birds may suffer from at least some form of the disease.

Allergic alveolitis may exhibit as either an acute, sub-acute, or chronic disease. Clinical signs are caused by a reduction of lung capacity and reduced alveolar-capillary diffusion due to a hypersensitivity reaction to feathers, dander, or feces. A person's lungs become unable to transfer oxygen from the air they breath into their blood stream.

The acute form usually develops due to an overwhelming antigenic load to a previously sensitized individual. An example of this would be cleaning out an enclosed cockatiel aviary where discarded feathers and feces have not been disposed of on a daily basis, but have been allowed to build up for weeks at a time. Symptoms develop 4-8 hours after exposure and include a cough, labored breathing, fever, and chills. If exposure is stopped at this point, no treatment is needed. The individual will return to normal.

Chronic, low grade exposure is much more serious. Symptoms may be masked or mistakenly diagnosed as a cold or flu. Affected individuals exhibit a chronic non- productive cough, exercise intolerance, and weight loss. Permanent pathological lung lesions may develop, including pulmonary lung fibrosis, leaving the individual scarred for life. Chronic allergic alveolitis can develop in as little as 2 years, although most people take 10-20 years to develop this severe form. The disease may be precipitated through exposure to a single budgerigar, and seems to have little correlation to the number of birds kept in the household. One budgerigar owner suffered from a recurrent influenza like illness that occurred every other week. The clinical signs were eventually linked to the biweekly cleaning of bird cages.

Patients diagnosed as having chronic allergic alveolitis may have no choice but to eliminate all exposure to birds. Some individuals find that they need to sell their home because they are unable to remove all the inciting antigens (e.g., the bird dander, feathers and dust). Re- exposure to minute quantities of feathers, dander or feces may precipitate a recurrence of symptoms. In less severely affected individuals, precipitating antibodies will regress in time and they are able to resume their avicultural practices.

In part, the severity of this disease can be lessened by wearing face masks when cleaning cages, frequently bathing birds, daily cage cleaning schedules and installing effective air filtration systems. People who have a history of allergic hypersensitivity reactions should take as many steps as possible to lessen their contact with allergens and consult their doctor if they develop a chronic cough or exercise intolerance. Don't ignore early symptoms, because by the time advanced symptoms develop, it may be too late. People may die from this disease or go through the heartbreak of living without birds.

People wishing to read an excellent, in-depth article on this disease are referred to Dr. Cathy A. Johnson-Delaney's presentation in the Association of Avian Veterinarian's 1989 Annual Proceedings.

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