🩺 Health & Disease · 7 min
Aspergillosis
Why this matters
The manual calls it the most lethal disease likely to occur in birds of prey, and says outright that prevention is the only successful method of control.
By the end of this lesson you will be able to
- Describe how aspergillosis presents and how fast it progresses
- Identify the species and circumstances most at risk
- State the prevention measures that actually work
What it is
A fungal infection, Aspergillus fumigatus, attacking primarily the respiratory system. Granulomas form as the body tries to wall the fungus off. It is usually lethal, and the great problem is that by the time clear symptoms appear the disease is already advanced.
The fungus lives in the environment, especially in organic matter and damp surroundings. It is not transmissible bird to bird. Birds of any age can get it.
The presentation
Early: decreased tolerance to exercise, heavy breathing after a short flight, sometimes a change in voice.
Later, and this is the case the exam builds a long stem around: the bird becomes suddenly more tame and well-mannered even when it should be acting wild, refuses to eat well, is reluctant to exert itself, bates weakly with heavy breathing and exhaustion, shows extreme thirst, and bends forward from abdominal pain, eventually picking at food and flicking it away.
That sudden docility is the trap. It reads as progress in manning. It is a dying bird.
The end comes fast: usually within a week, sometimes two days. Weight loss is dramatic.
Who gets it
Most frequently seen in Goshawks and Gyrfalcons; arctic and subarctic species are more susceptible than southern ones. Stressed birds are at higher risk: birds in training, birds after a change in management, first-year birds, and birds on long-term antibiotics or steroids.
Prevention is the whole strategy
Treatment is very difficult. Ancobon and amphotericin B have shown occasional limited success, and treatment must include supportive care and may need a combination of antifungal drugs. Despite proper treatment the condition is often fatal. So:
- Keep the environment clean and dry.
- Use mews substrates that do not support mould growth. Avoid hay, straw and dampness generally.
- Reduce stress.
- Optimise the bird's general health.
Two related points
Birds showing aspergillosis symptoms should also be treated for pneumonia, with antibiotics, stress reduction, good food and quiet. Birds with pneumonia tend to eat well, which helps distinguish the two. And fungal infections are often associated with other medical problems: decreased immune function invites parasites and secondary bacterial infection, and dehydration can lead to gout.
From the field
Your goshawk, three weeks out of the trap, has become lovely to handle. She sits calmly, does not bate, and is off her food. What is your first thought? Not that manning is going well. A wild-caught bird that turns suddenly docile and stops eating is the classic aspergillosis picture, and you have perhaps a week.
This lesson is part of the NY Falconry Exam course. Open it in the course to answer the retrieval checks that go with it, track what you have read, and quiz the whole unit. Lessons, quizzes and the glossary are free.