C. gattii Infection

Cryptococcus gattii (C. gattii) is a fungus that can cause a disease called cryptococcosis. Cryptococcosis usually affects the lungs or the central nervous system (the brain and spinal cord), but it can also affect other parts of the body. Brain infections caused by C. gattii and other types of Cryptococcus are called cryptococcal meningitis.

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History

In the United States, scientists have found that C. gattii (previously known as C. neoformans serotypes B and C) has caused infections in humans and animals in California since at least the 1960s.3 Until the past few decades, C. gattii was not known to cause locally acquired infections elsewhere in the United States. However, in 2004, scientists found that different strains of C. gattii were causing illness in the Pacific Northwest (Oregon and Washington) after having been found in neighboring parts of Canada a few years earlier.3–8 Since then, scientists have found that people have gotten C. gattii infections in other areas of the United States, particularly in the Southeast, without a history of travel to the West Coast.7 This suggests that C. gattii likely exists in the environment in many regions of the country. Scientists are still learning more about where it lives and why certain people get infected.

Riskfactors

Anyone can be infected with C. gattii if they’ve been in an area where the fungus lives in the environment. However, in different parts of the world, different characteristics may make some people more likely to get C. gattii infections than others.

For example, in Australia and New Zealand, C. gattii infections are thought to be more common among:

• People who are otherwise healthy,
• Males, and
• Aboriginal peoples

In British Columbia, Canada, the disease is more likely to occur in people who:

• Have weakened immune systems, for example, because of:
• HIV/AIDS
• Cancer treatment
• Medications that weaken the immune system such as corticosteroids
• Have other lung conditions
• Are 50 years of age or older
• Smoke tobacco

Scientists are still learning about why C. gattii appears to affect different groups of people in different areas of the world.

Is C. gattii infection contagious? No. The infection can’t spread between people, or between people and animals.

Source

C. gattii lives in the environment, usually on trees, in tree hollows, and in the soil around trees. The fungus primarily lives in tropical and subtropical areas of the world. It also lives in mainland British Columbia, Vancouver Island, the U.S. Pacific Northwest (Oregon and Washington), and California. Some people from other parts of the United States have gotten C. gattii infections without traveling to the West Coast, suggesting that C. gattii may also live in other areas of the United States, such as the Southeast.

Life cycle of C. gattii

C. gattii infections are not contagious. Humans and animals can become infected with C. gattii after inhaling dried yeast cells or spores in air. C. gattii travels through the airway and enters the lungs. The body’s temperature allows C. gattii to transform into its yeast form, and the cells grow thick outer layers to protect themselves. The yeasts then divide and multiply by budding. After infecting the lungs, C. gattii can travel through the bloodstream to infect other areas of the body, such as the central nervous system.

Signs and symptoms

The incubation period of C. gattii infection is not well-established. Symptoms of C. gattii infection can appear between two and 13 months after breathing in the fungus, with an average of approximately six to seven months.4,5 However, people can develop an infection as soon as two7 weeks or as late as three years after breathing in the fungus. C. gattii usually infects the lungs or the central nervous system (the brain and spinal cord), but it can also affect other parts of the body. The symptoms of the infection depend on the parts of the body that are affected.

In the lungs A C. gattii infection in the lungs can cause a pneumonia-like illness. The symptoms are often similar to those of many other illnesses, and can include:

• Cough
• Shortness of breath
• Chest pain
• Fever
• In the brain (cryptococcal meningitis)

Cryptococcal meningitis is an infection caused by C. gattii and other types of Cryptococcus after it spreads from the lungs to the brain, but patients can have a brain infection without a lung infection.

The symptoms of cryptococcal meningitis include:

• Headache
• Fever
• Confusion or changes in behavior
• Neck pain
• Nausea and vomiting
• Sensitivity to light

C. gattii infection can also cause cryptococcomas (fungal growths) to develop in the lungs, skin, brain or other organs, causing symptoms in the affected parts of the body.

Diagnosis

Healthcare providers use your medical and travel history, symptoms, physical examinations, and laboratory tests to diagnose a C. gattii infection.

Your healthcare provider will take a sample of tissue or body fluid (such as blood, cerebrospinal fluid, or sputum) and send the sample to a laboratory to be examined under a microscope, tested with an antigen test, or cultured . Your healthcare provider may also perform tests such as a chest x-ray or CT scan of your lungs, brain, or other parts of the body.

Testing serum (a component of blood) or cerebrospinal fluid for cryptococcal antigen is useful as a first test for cryptococcal infection, but the test doesn’t tell the difference between Cryptococcus neoformans and Cryptococcus gattii. Culture is traditionally used to tell if a cryptococcal infection is due to C. neoformans species complex or C. gattii species complex.

Treatment

People who have C. gattii infection need to take prescription antifungal medication for at least 6 months, often longer. The type of treatment usually depends on the severity of the infection and the parts of the body that are affected.

For people who have asymptomatic infections or mild-to-moderate pulmonary infections, the treatment is usually fluconazole. For people who have severe lung infections or infections in the central nervous system (brain and spinal cord), the recommended initial treatment is liposomal amphotericin B in combination with flucytosine.

After initial antifungal therapy, patients usually need to take fluconazole for an extended time to clear the infection. Some people will need lumbar punctures to get rid of increased pressure in the brain. Some people will also need corticosteroids. The type, dose, and duration of antifungal treatment may differ for certain groups of people, such as pregnant women, children, and people in resource-limited settings. Some people may also need surgery to remove fungal growths (cryptococcomas).

Statistics

C. gattii infections are rare. Worldwide, many of the reported cases of C. gattii infections have occurred in North America, Australia, and South America. Most of the reported C. gattii cases in the United States are from Oregon, Washington, and California. However, a small number of cases occur in other states.

Prevention

There are no formal recommendations to prevent C. gattii infection. Most people breathe in small amounts of many fungi every day but never become sick. If you have symptoms that you think may be caused by C. gattii, you should see a healthcare provider as soon as possible.

C. gattii Infection Resources
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