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Avian Aspergillosis

November 13, 2009

I’m posting this for those whose bird is caught in the battle of aspergillosis.  

The following is an excerpt from the writer’s “Selecting an Avian Veternarian for Your Bird” post …. following the excerpt is a more technical writing about Avian Aspergillosis by Dr. Ken Welle.


Writer’s note:  If you are fortunate to have an avian veterinarian diplomate within a relatively close distance, you are one lucky person!  I have actually driven a total of six hours (three hours each way) to have my birds treated by an avian diplomate.  I initially located this veterinarian when Amigo was diagnosed with aspergillosis (aspergillus [mold]).  The first veterinarian I took her to, when she had not yet been diagnosed with asper, came back into the examination room to tell me that she had an 80%.  Of what?  Of dying.  I then immediately drove to one of the top rated avian veterinarians in the city (my usual avian veterinarian).  After examining Amigo, he gave her a 50% chance of surviving.  The veterinarian began her treatment by prescribing Amphotericin B mixed with Saline solution (nebulized), and Ancobon mixed with Lactulose (administered orally).  I decided to further research asper, and within a few days I contacted a top avian aspergillosis expert, Dr. Pat Redig, Co-Founder and Director of The Raptor Center / University Minnesota – Minneapolis.  Dr. Redig suggested that Amigo would benefit from using Itraconazole, a fungicide.  Amigo’s current veterinarian refused to change the medications, stating that he was “comfortable” with the medications he currently had her on.  I then contacted World Bird Sanctuary and spoke with Walter Crawford, Executive Director, in hopes of locating a veterinarian that was more familiar with aspergillosis.  I explained that per Dr. Redig’s suggestions, Amigo needed to be placed on a more aggressive treatment plan.  Walter put me in contact with two veterinarians who worked at the sanctuary.  Amigo was finally placed on Itraconazole.  It was also decided to continue nebulizing Amigo with Clotrimazole and Saline solution, which had been prescribed by the prior avian veterinarian.  In the interim, friends that had recently lost their African Grey to aspergillosis told me about Dr. Ken Welle, an avian diplomate.  They told me that Dr. Welle had an 80% success rate in the treatment of aspergillosis.  The following day I put Amigo in my car, and took off for Dr. Welle’s clinic.  After examining Amigo, Dr. Welle told me that we could get her through this.  And we did.  Amigo was treated for aspergillosis for approximately four months.  Amigo was pulled off of Itraconazole on December 13, as liver problems were suspected.  Amigo was tested again for aspergillosis and liver problems on December 15.  Samples for aspergillosis testing were submitted to the University of Miami.  The liver test results indicated that indeed, the fungicides were beginning to effect her liver.  I was notified of the aspergillosis test results on December 20.  Antigens were negative, antibodies positive.  The test results proved to be a wonderful Christmas present! 

 This experience has convinced me that there are some situations that need the advanced knowledge and expertise that only avian diplomates can provide.  I truly doubt that Amigo would have recovered from the fungus had I not put her under the care of an avian diplomate.  And those that  question my belief on this subject will never change my mind.


Aspergillosis is a disease caused by the growth of Aspergillus mold (fungus) in an animal’s body.  It is generally a respiratory disease but on rare occasions will penetrate other organs and develop granulomas.  Aspergillus is considered to be a ubiquitous (i.e. present nearly everywhere) organism.  So why don’t all animals develop aspergillosis?  Normally, there is a balance between the number of fungal spores that are inhaled by the bird, and the immune system of the bird.  Under certain environmental conditions (high humidity, corn cobbit bedding, poor sanitation, poor ventilation, old food), the Aspergillus mold thrives and will produce massive number of spores.  When such large numbers of spores are inhaled by the bird, the immune system is overwhelmed and acute aspergillosis will occur.  Additionally, when high populations of the mold are present, toxins (aflatoxins) are produced and can cause separate problems.  On the other hand, continual, low level stresses such as poor nutrition, very dry air, rapid temperature changes, overcrowding, capture, or shipping will allow the normal numbers of spores to overwhelm the compromised immune system.  In some wild birds, simply being in captivity may provide this stress.  The result is chronic aspergillosis.  It only stands to reason, then, that the way to avoid this disease is to control stress and to avoid environmental conditions conducive to its growth.  Aspergillosis can occur in an acute form where the bird develops severe, life threatening respiratory difficulty very suddenly.  Most of these birds will die before a diagnosis can be made.  A granuloma often forms in the syrinx causing suffocation in these cases.  This form appears to be particularly common in Amazon parrots.  This disease also occurs in a chronic form.  Birds with chronic aspergillosis follow a long course of weight loss, general poor health, and variable levels of respiratory distress.  African Grey parrots are predisposed to this form of aspergillosis.  Diagnosis is often challenging but usually involves hematology (leukocytosis, heterophilia, monocytosis), radiography (focal air sac opacities), fungal cultures (from nasal flush, tracheal wash, air sac swabs), and sometimes even biopsies.  Antibody titers are useful when aspergillosis is suspected but the organism cannot be isolated.  Treatment of this disease is difficult.  Owners should be given a guarded prognosis and should be warned of the cost and duration of treatment.  This is due to the fact that the granulomas that form are not easily penetrated by drugs.  Smaller granulomas may eventually resolve with long-term antifungal therapy.  The protocol for treatment of aspergillosis consists of systemic (IV), and topical respiratory (intratracheally or nebulization) therapy with amphotericin B combines with long term therapy with one of the oral azole antifungals or with flucytocine.  Amphotericin B seems to have less effect on the kidneys of birds compared to mammals.  However, fluid therapy and monitoring the urine for the development of casts if very important.  Casts will form long before elevation of uric acid occurs.  Itraconazole appears to have the greatest activity against aspergillosis of all of the systemic azoles.  Clotrimizole, when dissolved in polyethylene glycol appears to be very effective following long term (months) nebulization therapy.  Follow up, including hematology, radiography, and endoscopy is very important in determining response to therapy.  Larger granulomas may require surgical removal.  In one study an autogenous mycotin (vaccine) was effective both in prevention and treatment of aspergillosis in a wildlife rehabilitation center. 

Dr. Kenneth Welle, All Creatures Animal Hospital

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