by Janet Alexander
Aspergillosis is the most common fungal infection found in birds and has been known to transmit to humans under certain conditions.
The disease is contracted as the result of inhalation of spores. It may also be contracted by oral ingestion. In birds, as well as their human counterparts, the disease is usually developed when that individual has a compromised immune system, which may be suppressed by a concurrent illness, malnutrition and most especially, stress.
Aspergillosis is frequently seen in birds subjected to surgery, reproduction, environmental changes, and confinement or transporting. We commonly see this disease in raptors that come to our Center during the winter months when conditions for the fungus are optimal.
Aspergillus spp. are fungi spores commonly found in soil, water and decaying vegetation. The fungi grow in damp, dark conditions with poor ventilation. Dried fecal matter, damp or contaminated food material, or dirty feeding utensils may encourage mold growth.
Aspergilla may affect the lower respiratory tract, and even the intestinal tract and other organs. Although lungs and air sacs are usually involved, the trachea, syrinx, and bronchi may be affected as well. Infection can spread from the respiratory tract to become pneumonia or enter the peritoneal cavity. Patients exhibit labored breathing, severe depression and extreme emaciation. Unfortunately, for birds, the mortality rate is exceptionally high.
Diagnosis in avian subjects can be difficult, at best, other than by necropsy. Tentative diagnosis can sometimes be made with clinical signs of the disease. A qualified veterinarian should institute appropriate treatment. Treatment protocols are tailored to the individual bird, usually including aggressive antifungal treatment, surgery, and nebulization, and in some cases, sinus flushings are warranted.
In humans, diagnosing pneumonia due to Aspergillus spp. is often difficult without performing invasive procedures such as lung biopsy. However, there are several diagnostic measures and once identified, the disease can be managed through a course of antibiotic treatment with excellent results.
When working with birds in a rehabilitation capacity, the following questions should be considered:
- Are you immune-compromised in any way?
- Are you working with susceptible species (such as raptors)?
- Are you rehabbing in a damp environment which may harbor fungal spores?