Cryptococcosis is transmitted through inhalation of the airborne fungus C. neoformans, which is contained in particles of soil and bird droppings. Because cryptococcosis can be transmitted through pigeon droppings, it’s largely an urban infection. Cryptococcosis isn’t transmitted from person to person. It’s more prevalent in men than women, usually those between ages 30 and 60, and is rare in children. Cryptococcosis also occurs in dogs, cats, horses, cows, monkeys, and other animals.

Cryptococcosis is especially likely to develop in immunocompromised individuals, such as those with Hodgkin’s lymphoma, sarcoidosis, leukemia, or lymphoma, and in those who are receiving immunosuppressive agents. People with acquired immunodeficiency syndrome (AIDS) are by far the most commonly affected group today, accounting for more than 80% of all cases. However, people without compromised immune systems develop cryptococcosis occasionally as well.

Cryptococcosis may cause ataxia, optic atrophy, hydrocephalus, deafness, paralysis, chronic brain syndrome, and personality changes. Without treatment, meningitis results in death within weeks to months. In immunocompromised patients who develop cryptococcal meningitis, the overall mortality rate following treatment is nearly 30%. Of those who survive, 40% have significant neurologic deficits, including vision loss, decreased mental function, hydrocephalus, and cranial nerve palsies. Relapse occurs in 20% to 25% of patients.

Symptoms commonly begin 2 to 11 months after exposure to C. gattii; the incubation period for C. neoformans is unknown. Typical signs and symptoms of cryptococcosis include fever, cough with pleuritic pain, shortness of breath, night sweats, weight loss, weakness, and CNS disturbances. CNS involvement occurs gradually (cryptococcal meningitis) and causes progressively severe frontal and temporal headache, fatigue, diplopia, blurred vision, dizziness, ataxia, aphasia, vomiting, tinnitus, memory changes, inappropriate behavior, irritability, psychotic symptoms, seizures, and fever. Left untreated, CNS symptoms will progress to coma and death, usually as a result of cerebral edema or hydrocephalus.