Sunday, September 25, 2011
Allergies to Birds and Bird Keeper's Lung
My previous blog about having your bird sleeping in the bedroom generated a lot of interest. I had several requests to explain a bit more about the different forms of "Bird Keeper's Lung" so I have taken an excerpt from an article I had written about Pet Bird Zoonoses (diseases you can get from your bird) which discussed allergies to birds and Bird Keeper's Lung.
Allergies to Birds
Clinical signs in people with allergies to birds include malaise, chills, fever, shortness of breath, myalgia and coughing. Hypersensitivity pneumonitis and interstitial pneumonia in humans have been associated with exposure to feathers, aerosolized droppings and other agents. Inhaled avian source antigens can cause severe disease in hypersensitive individuals. If there are exposures to avian antigens it can severely compromise health and quality of life. It is believed that the allergic response is due to bacterial endotoxins in fecal extracts. The conditions subside after no further exposure to the antigens.
Hypersensitivity Pneumonitis (Pigeon Breeder's Lung, Bird Keeper's Lung)
Extrinsic, allergic, alveolitis ( EAA)- three forms, acute, subacute, chronic
Four to eight hours after heavy exposure to avian antigens. Dry cough, shortness of breath, fever, chills. No therapy needed. Resolves in 24 hours.
Diagnosis through clinical history, serum precipitin test, intradermal skin test ( feather, feather dust "bloom", fecal extract ), lung function tests, radiographs, bronchial inhalation challenge. Most commonly seen from exposure to pigeons. Large dose of antigen ( Cleaning loft ) in a short period of time. Feathers, dust, aerosolized droppings (bacterial proteins/endotoxins) common antigens.
Wearing respirators/masks may help but dusts may still be present on clothes or still in the environment.
Long term continuous exposure. Fairly constant dry cough/progressive dyspnea.
Diagnosis more difficult as no "trigger event". Positive lab tests to avian antigens.
May require steroid therapy. Complete cessation of exposure to avian antigens. Prognosis is good but is a step in the progression to chronic disease.
Progressive exertional dyspnea. Non-productive cough, end inspiratory rales, hypoxemia at rest, worsened during exertion. Pulmonary fibrosis with decrease in lung function - at this point it is irreversible, terminate exposure to prevent further deterioration. Low dose exposure to antigen over long periods.
Diagnosis as with other forms. Hypersensitivity skin test. No readily apparent acute signs to show disease developing to irreversible pulmonary fibrosis. Early signs mimic flu or mild respiratory disease. No correlation between the severity of disease and the number of birds kept (one budgie can cause the same degree of pathology as 400 birds in home aviary of a hypersensitive individual). Chronic EAA is seen in individuals with more than two years exposure to birds. Older individuals have faster decline of lung function.
Seek medical attention for respiratory irregularities, especially non-resolving cough conditions and breathlessness upon exertion or even mild exercise. Smokers have a lower incidence than non-smokers in comparable bird owning populations as tobacco smoke reduces exposure of antigen to alveoli by contributing to airway obstruction. Impairs function of pulmonary macrophages lining the alveoli. Problems due to smoking may mask signs of disease and co-exist. Treat as above. Irreversible changes occur.
We have seen an increase in this condition throughout the years. Perhaps it is better recognized or due to an increase in birdkeeping. As can be garnered from the above discussion it is a very serious disease condition, unrelated to the number of birds kept, especially if the person is already hypersensitive. The best advice that can be given is to reduce exposure to the aerosolized material.
1) Keep your birds restricted in one room or a couple of rooms. You need the opportunity to get away from the antigens. If birds are in every room of the house you cannot get away from it, heightening your risk. The danger is even greater if the birds are in your bedroom as you will inhale that material all night long.
2) Clean the cages regularly (daily is ideal) because if you can prevent the feces from drying/aerosolizing your risk will be reduced. Also regular cleaning will reduce bacterial buildup and make the environment healthier for your birds.
3)Buy a quality air cleaner to reduce the disease causing material in the environment. There are many excellent air cleaners available and for a reasonable investment you can provide a safer environment for your family, human and avian.
4)If you must be around the birds or during cleaning and you have shown some sensitivity, wear a mask of some type, such as a surgical mask to reduce exposure.
I am glad many of you have read this and are concerned about the potential for this disease in hypersensitive individuals. With the implementation of the precautions listed above the risk of developing the disease condition can be minimized. If you or anyone in your family is exhibiting any of the above symptoms be sure to speak to your family physician about the possibility of this disease.