Cryptococcus neoformans is a type of yeast that, when it affects a human, causes cryptococcosis. Healthy people with functioning immune systems almost never suffer infections, but the immunocompromised and persons with AIDS are prone to such infections.
The disease causes both lung and neurological symptoms. If symptoms are limited to the lungs, fluconazole is usually effective. However, once neurological symtoms appear, the patient must be treated with amphotericin B.