Aspergillosis
Basics
Overview
Aspergillosis is a fungal disease caused by Aspergillus fumigatus, an opportunistic fungal
organism that is found in most environments.
Stress, malnutrition, steroid use, prolonged antibiotic use, immune suppression, and poor
hygiene are all possible reasons for the development of infection.
Infection usually develops within the respiratory tract and although early signs may be subtle
they may include; lethargy, decreased appetite, change or loss in voice, and increased breathing
rate and/or effort.
Signalment
All pet birds can develop disease, but the most commonly affected psittacine birds are the African Grey
Parrot, Pionus spp., and Amazon Parrots.
Signs
Labored breathing
Change or loss in voice/call
Lethargy
Not eating, lack of appetite; weight loss
Causes
Impaired respiratory function is usually caused by large colonies of fungal growth (i.e.,
granulomas) that can obstruct airways or invade the air sacs, causing inflammation and affecting
the exchange of oxygen.
Poor husbandry/hygiene practices can cultivate an environment where infection is imminent.
Risk Factors
Environmental factors: poor husbandry/ventilation, use of particulate bedding (wood shavings,
corn cob or walnut-shell bedding, litter, etc)
Nutritional disorders/deficiencies (Vitamin A deficiency)
Stress
Impaired immune function
Prolonged antibiotic use or inappropriate use of steroids
Treatment
Appropriate Health Care
Hospitalization and supportive care may be required dependent upon how ill the bird is. Tube
feeding and supportive fluids may be required to help maintain the patient’s immune function
and ability to metabolize the required antifungals appropriately.
Activity
Restricted physical activity and reduced stress is paramount throughout treatment. This may be
achieved at home by providing a warm, dark, and quiet environment.
Diet
A fresh and nutritionally balanced diet should be always available to the patient. If the bird stops eating,
hospitalization and supportive care is strongly advised.
Surgical Considerations
Very localized infections (granulomas) can sometimes be removed via endoscopy and the area may also
benefit from topical treatment during the surgical procedure.
Medications
Medications in this section are intended to provide general information about possible
treatment. Combination therapies, involving oral, injectable, and nebulized medications have all
been proven to be useful and treatment guidelines are dependent upon the severity of the
specific case.
Antifungals like itraconazole, amphotericin B, fluconazole, and terbinafine are prescribed based
primarily on the species being treated and general location of the infection. It is not uncommon
for treatment to be required for months, until the infection is proven to be cleared. Certain
species, specifically the African Grey Parrot, have been shown to be sensitive to itraconazole
administration.
Antibiotics may also be prescribed to help eliminate any possible secondary bacterial infections
from emerging.
Follow-Up
Patient Monitoring
Serial imaging tests (radiographs/x-rays) and/or endoscopic evaluation may be useful in tracking
the progression of disease or success of treatment.
Treatment with antifungal medications should extend at least 1 month after a normal complete
blood count (CBC) is seen.
Biochemistry panels should be frequently assessed to help the attending veterinarian
understand how the medications are affecting the patient.
Possible Complications
Progression of the disease, despite aggressive treatment, is possible.
Patient sensitivity to certain antifungals may make it difficult to formulate an effective
treatment plan.
Expected Course and Prognosis
Treatment of aspergillosis often has the best outcome when the disease is caught during the
early stages. Unfortunately, the disease is often not diagnosed until it is in the advanced stages
making a poor outcome all too common.
Infection may relapse if environmental factors that previously exposed the patient have not
been addressed.
Life-long respiratory signs may be observed due to the chronic inflammation caused by the
infection.
Key Points
African Grey Parrots, Amazon Parrots, and Pionus Parrots are the most commonly affected
species within the psittacine species.
Aspergillosis is generally a preventable disease. A complete and balanced diet, stress-free
environment, and good hygiene (reducing the bird’s exposure to fungal spores) are all important
to decrease disease occurrence.
Signs of aspergillosis are often subtle and nonspecific; making early diagnosis of the disease
difficult. To further complicate early disease detection, diagnosis is difficult and usually involves
the use of several different tests (blood work, imaging, endoscopy, cultures, etc).
Treatment often requires combination therapies, frequent visits to the veterinarian for
treatment assessment, and may require months of dedication from the owner.
NOTES
