What causes aspergillosis?
Aspergillosis is caused by a fungus (Aspergillus), which is commonly found growing on dead leaves, stored grain, compost piles, or in other decaying vegetation. Dirt, dust, or other materials containing Aspergillus can easily travel through the air and be inhaled into the lungs. People who smoke marijuana, which can contain Aspergillus spores, may be at an increased
risk of developing aspergillosis.
It causes illness in three ways: as an allergic reaction in people with asthma (Pulmonary aspergillosis - allergic bronchopulmonary type); as a colonization and growth in an old healed lung cavity from previous disease (such as tuberculosis or lung abscess) where it produces a fungus ball called aspergilloma; and as an invasive infection with pneumonia that is spread to other parts of the body by the bloodstream (Pulmonary aspergillosis - invasive type).
The invasive infection can affect the eye, causing blindness, and any other organ of the body, but especially the heart, lungs, brain, and kidneys. The third form occurs almost exclusively in people who are immunosuppressed because of cancer, AIDS, leukemia, organ transplants, high doses of corticosteroid drugs, chemotherapy, or other diseases that reduce the number of normal white blood cells.
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. |
