Cryptococcus is microscopic fungus, a few species (kinds) of which can cause deadly disease. Cryptococcus is found throughout the world in soil, trees, and bird droppings. The fungus is usually harmless, but two species can cause significant disease in people. Cryptococcus neoformans causes disease and death mostly in people with damaged immune systems. Cryptococcus gattii can cause disease and death in healthy people. Worldwide, Cryptococcus causes over 1 million cases of disease and about 600,000 deaths each year. Most cases occur among AIDS patients in Africa south of the Sahara.
Cryptococcus infection starts when the fungus is inhaled into the lungs. From the lungs, it can move to the central nervous system and other parts of the body. The person may develop a severe headache, fever, stiff neck, blurred vision, or difficulty breathing. Doctors diagnose the disease when they find cryptococcus cells in a fluid or tissue sample from the patient. They treat the infection with antifungal drugs.
In Africa, people whose immune systems have been compromised by AIDS often develop fatal illness caused by C. neoformans. In many regions of Africa, lack of antifungal medications contributes to many deaths. C. gattii is generally found in places near the equator, where it occasionally causes disease in healthy people and animals. Since 1999, C. gattii has caused an increasing number of infections in people and animals in the U.S. Pacific Northwest and on Vancouver Island in Canada. Many of these infections have been fatal.
Researchers are studying how the fungus causes disease in humans and other animals. Scientists are also working to discover how different varieties of Cryptococcus originate and spread to new environments. They hope that the research will eventually lead to better prevention and treatments for disease caused by Cryptococcus.
