Aspergillus and Birds

Aspergillosis is a Serious and Often Fatal Fungal Disease of Birds

Apr 13, 2007

Birds inhale or ingest spores of Aspergillus fungus in warm moist environments. Aspergillosis is a serious fungal infection.

Fungi belonging to the Genus Aspergillus are common in the environment. They flourish in warm moist environments where there is abundant decaying organic matter, particularly plant material. Aspergillus spp. frequently cause infection in animals and humans; in birds and humans it is usually Aspergillus fumigatus, but other species can cause problems as well.

When Aspergillus sp. is actively growing, it produces tiny rounded heads covered with long chains of spores. The head looks a bit like a dandelion flower gone to seed, but instead of all the umbrella-like seeds, there are hundreds of chains of microscopic spores. The spores break off easily and scatter through the nearby decaying matter to start new fungal growth, or become airborne and drift away on air currents. A single patch of growth of Aspergillus sp. produces millions of spores—these fungal spores are everywhere.

How do birds catch aspergillus?

Birds catch aspergillus when they consume moldy feed or sift through moldy litter and vegetation with their beaks and bills, inhaling the spores. Pet birds and domestic birds are at risk if their feed or litter has been stored in a warm damp place where the fungus can begin to grow. Wild birds sometimes die in huge numbers when flocks feed on moldy grain, particularly corn, or on other damp and moldy food sources in the wild. Water birds and scavengers are often victims of the disease.

Eggs laid in moldy litter can become infected when the fungus penetrates the eggshell and begins to grow on the inner membrane. Some chicks hatch with fungal infections already established. Others pick up the fungus as they break out of the egg.

Birds that are very old, very young, or suffering from other health problems are more susceptible to aspergillosis than most birds. Stressed birds are also at greater risk—birds that are having difficulty in the wild, birds that have recently been caged, and pet birds that are not well cared for and kept in poor conditions. The disease is not passed from bird to bird.

The infective dose—the number of spores that a bird must inhale or swallow in order to become ill—is thought to be about 17 million for adult birds, and about 5 million for chicks. Though this sounds like a lot, when the fungus is actively producing spores, a single bag of moldy feed would have many times more spores than this.

What are the symptoms of aspergillosis in birds?

A bird with aspergillosis typically has labored, rapid breathing. It may have difficulty walking and behave oddly. It may also have diarrhea, and suffer from lack of appetite, weight loss, sleeplessness, and increased thirst. Fungal growth in the eyes causes cloudiness and discharge.

Aspergillosis is very difficult to treat and there is little hope of recovery unless the infection is diagnosed and treated very early. Treatment should only be attempted under the care of a veterinarian.

Articles about other bird diseases:

Sources:

Rand, Michael S. "Summary of Avian Diseases: Fungal, Nutritional, Tumors, Parasites and Miscellaneous" Wrair Seminar. 1986.

The copyright of the article Aspergillus and Birds in Birds is owned by Rosemary Drisdelle. Permission to republish Aspergillus and Birds in print or online must be granted by the author in writing.