Aspergillosis is a common cause of respiratory disease in pet birds. It can cause upper and lower respiratory problems or a more broadly distributed infections.
What is Aspergillosis?
Aspergillus is the fungus that causes a disease called aspergillosis. This slow growing fungal infection gradually damages tissues in the body over a period of weeks to months, with little obvious evidence of illness until an organ or system is severely compromised. Aspergillus is found everywhere, particularly in soil, nesting material and moldy foods.
"It appears that birds on an all seed diet are prone to this disease."
Aspergillus is normally an environmental contaminant and does not seem to be spread easily between birds. Often, other diseases that have compromised the bird's immune system will predispose a bird to secondary Aspergillosis infection. Steroid use, long term antibiotic use, too much stress, poor husbandry or hygiene, respiratory irritants (such as cigarette smoke), viral infections and chronic infections can all cause immune suppression. It appears that birds on an all seed diet are prone to this disease. It is suspected that most birds are regularly exposed to this fungus, but healthy ones do not get sick.
How do I know if my bird has Aspergillosis?
Aspergillosis does not show any specific signs and may be undetectable by your veterinarian unless it is on the skin. There may be signs of respiratory difficulty, tail bobbing, or weight loss. The bird may be depressed, fluffed and listless. A veterinarian familiar with birds will start with a complete history, weight and a physical examination. Since many of the clinical signs are descriptive and are common to several different diseases, diagnostic tests are advised.
What tests can be done?
Many different tests may be employed if aspergillosis is suspected. Each test provides another piece of the puzzle and often multiple tests are needed to give more clarity.
A complete blood count (CBC) with a dramatic elevation in the white blood cells may initially raise suspicion of an Aspergillus infection. X-rays will usually only show subtle lesions in an advanced stage of disease. Serology tests are available but can have false negative results. DNA tests will detect the presence of Aspergillus DNA. A Tracheal wash can illustrate the presence of the Aspergillus organism in the trachea or respiratory tract. The most accurate diagnostic technique is surgical laparoscopy in which a fiber-optic instrument is passed surgically into the bird to view the air sacs and lungs. Biopsies or samples of lesions are collected, and evaluated by cytology and histology. Cultures of the collected samples may grow the organism.
Can my bird be treated?
Aspergillosis is a very challenging disease to cure. The location of the infections and the way the body attempts to wall off the fungus both restrict the ability of drugs to get to the fungus. Treatment takes a long time. The bird must have a strong immune system in order to completely eliminate the organism. Treatments may include oral, intravenous and aerosolized antifungal medications and/or surgical removal of fungal plaques. Supportive care includes hospitalization, oxygen therapy, providing warmth, force feeding and treating any other underlying or concurrent diseases.
"Aspergillosis is a very challenging disease to cure."
Good hygiene, clean environment, fresh clean food items and strong immune system are necessary to help prevent future outbreaks of aspergillosis.
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