Cryptococcosis is a fungal infection, which is also known as neurocryptococcosis. Cryptococcus is a type of fungus usually associated with birds and their droppings but it lives in the environment throughout the world. Cryptococcosis transmission occurs through the inhalation of airborne fungi.

The main species of cryptococcus that causes illness in humans is Cryptococcus neoformans. Cryptococcus neoformans can be found in animals too, such as in dogs and cats. Most people who are exposed to the fungus, however, never get sick from it.

This infection is most often seen in people with a weakened immune system, such as those with:

  • HIV/AIDS
  • Hodgkin’s disease
  • People on chemotherapy for cancer
  • People taking corticosteroids, medication for rheumatoid arthritis and other medication that weakens the immune system

The infestation of this yeast-like fungus can lead to tumours in the lungs. It can also spread to the brain and cause cryptococcal meningitis (CM). It’s estimated that every year, nearly 1 million cases of cryptococcal meningitis are diagnosed worldwide and the disease accounts for more than 600,000 deaths. 

What are its symptoms?

Cryptococcus neoformans usually infects the lungs or the central nervous system (the brain and spinal cord), but can also affect other parts of the body. Symptoms depend on the parts of the body that are affected.

Infection in the lungs may cause a pneumonia-like illness. Symptoms can include:

Cryptococcal meningitis occurs when the infection spreads from the lungs to the brain. Its symptoms include:

People with a normal immune system may have no symptoms at all.

How is it diagnosed? 

A diagnosis typically relies on your medical history, symptoms, a physical examination and laboratory tests.

The doctor may perform the following tests: 

  • Blood test
  • CT (computerised tomography) scan 
  • Lung biopsy
  • Bronchoscopy (a test where an instrument called a bronchoscope examines your airwaves)
  • Spinal tap, or lumbar puncture, where a needle is inserted inbetween two vertebrae in the back to obtain a sample of cerebrospinal fluid (CSF)
  • Cerebrospinal fluid (CSF) culture and other tests to check for signs of infection
  • Chest X-ray
  • Cryptococcal antigen test (looks for a certain molecule that the Cryptococcus neoformans fungus can shed into the blood)

What are your treatment options? 

Cryptococcosis treatment depends on the severity of the infection and the parts of the body that are affected. Treatment may also differ for certain groups of people, such as pregnant women and children. 

If you have asymptomatic infections (diagnosed via targeted screening), or mild-to-moderate pulmonary infections, treatment is typically the medicine fluconazole.

If you have severe lung infections or central nervous system infections (brain and spinal cord), the typical drug treatment is amphotericin B in combination with flucytosine. Your doctor may recommend fluconazole for a period after that to clear the infection.

Some people may need surgery to remove fungal growths. 

Can it be prevented? 

Most of us probably breathe in this fungus as children but never get sick from it, while those whose immune systems are compromised from, for example, HIV/AIDS can fall seriously ill from it. Although it’s not possible to prevent initial exposure to the fungus as it is so common in the environment, diagnosing and treating early cryptococcal infections in immunocompromised people can prevent death from cryptococcal meningitis, for example. 

The accuracy of this information was checked and approved by physician Dr Thomas Blake in July 2016