Cryptococcus is a yeast-like fungus. C. neoformans and C. gattii are pathogenic for humans and can cause cryptococcosis; most clinical laboratories do not routinely distinguish between these species.

• Worldwide, there are ~1 million cases of cryptococcosis, with >600,000 deaths annually. Most cases are in pts with AIDS.
• Cryptococcosis due to C. neoformans is rare in the absence of impaired immunity; in contrast, C. gattii-related disease often occurs in immunocompetent pts.
• C. neoformans is found in soil contaminated with pigeon droppings, whereas C. gattii is associated with eucalyptus trees. Most cases are acquired via inhalation, which results in pulmonary infection.