What is aspergillosis and what causes it?
Aspergillosis is a respiratory disease of birds caused by the fungus Aspergillus, which is found almost everywhere in the environment. A. fumigatus is the most common species of the fungus to cause disease, although A. flavus, A. niger, and others can also cause problems. Aspergillus grows readily in warm and moist environments. The microscopic spores of the fungus become airborne, and poor ventilation, poor sanitation, dusty conditions, and close confinement increase the chance the spores will be inhaled. Usually, the fungus does not cause disease, however, if a bird does not have a healthy immune system, it can cause illness. Predisposing factors include other illnesses, stress, poor nutrition, poor husbandry or unsanitary conditions, another injury to the respiratory system (e.g.; smoke inhalation), and prolonged use of certain medications such as antibiotics or corticosteroids. The combination of the number of spores in the environment and the presence of predisposing factors deter
