A fungal infection that can affect the lungs and spread to other organs
Aspergillosis is caused by spores of the aspergillus fungus, which occur in dust, soil, and decaying plants. The spores are harmless if a healthy person inhales them. However, the fungus can cause lung disease and other serious illnesses in people who are vulnerable to infection because of particular sensitivity, pre-existing lung damage, or reduced immune function.
There are three forms of aspergillosis. In some people, a sensitivity to the fungus eventually develops into a disorder known as allergic bronchopulmonary aspergillosis, the symptoms of which are similar to those of asthma.
In people who already have damaged lungs as a result of a long-term disease, such as tuberculosis or bronchiectasis, the fungi spores may become lodged in cavities in the lung tissue caused by the disease. Eventually, the spores grow into masses known as “fungus balls”. This condition usually causes a cough that may be accompanied by bloody sputum.
The fungus can also cause a serious infection of the lungs in people whose immune systems are suppressed, such as those with AIDS (see HIV infection and AIDS) or those receiving chemotherapy. The result of this infection is a pneumonia-like illness. In severe cases, the infection may spread to other body organs, including the heart, brain, and kidneys.
Aspergillosis is diagnosed by examining a sample of sputum under a microscope to look for the fungus, by a blood test for antibodies, or by a skin prick test. A chest X-ray may also be carried out. Treatment usually involves antifungal drugs. It may be necessary to remove a fungus ball surgically. Aspergillosis is sometimes fatal in people who have impaired immunity.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.