a chronic fungal infection of humans caused by Cryptococcocus neoformans and C. bacillispora. The organism may be present in soil or dust and is often found in pigeon droppings, with resulting high concentrations on window ledges and around other nesting places. How humans become infected is not certain, but it is probably by inhalation of fungus-bearing dust. A large number of pulmonary infections due to cryptococcosis may go unreported; its symptoms include fever, malaise, and a dry cough. Nine-tenths of those cases of infection that are reported are of the more serious type known as disseminated cryptococcosis. In such cases, the fungus can spread from the respiratory system to the central nervous system, causing meningitis (inflammation of the membranes surrounding the brain). The principal symptoms of the meningitis are headache, blurred vision, and confusion, lethargy, or personality change. The Cryptococcus fungus can also spread to and cause lesions in the skin, bones, and visceral organs. Immunocompromised patients (e.g., those infected with HIV/AIDS or those receiving immunosuppressive drugs) are at particularly high risk of cryptococcosis.

All forms of cryptococcosis respond to amphotericin B, the survival rate of patients treated being approximately 80–90 percent. Before this therapy was available, there were few reported survivors of cryptococcal meningitis.