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Cryptococcus Gattii

Cryptococcal disease, or cryptococcosis, due to infection with spores of Cryptococcus gattii is a relative new-comer to the list of diseases native to B.C., first appearing in 1999. Disease due to this species of fungus is rare, but can be serious, resulting in pneumonia or meningitis. It can take several months to incubate after exposure. Fortunately, not many people exposed to the spores will become ill, and we are still learning much about it.

Cryptococcus gattii is related to C. neoformans, which occurs all over the world. C. gattii was previously associated with tropical and subtropical areas until it emerged on Vancouver Island. Around 2004, the fungus spread to the BC Lower Mainland and later into the Pacific Northwestern US. Vancouver Island has one of the highest rates of infection in the world. Although the fungus grows on land, in forested areas, dolphins have been known to get infected!

Information for Health Professionals

Cryptococcus is a tiny (microscopic) yeast-like fungus. A species of this fungus, called Cryptococcus gattii, has been living on trees and in the soil on the east coast of Vancouver Island since at least 1999. More recently it has also been found in the Vancouver Coastal and Fraser Health regions. Infrequently, people and animals (e.g. cats, dogs, llamas, porpoises) exposed to this fungus become sick with cryptococcal disease (or cryptococcosis). Cryptococcosis can affect the lungs (pneumonia) and nervous system (meningitis) in humans. It affects people with healthy and weakened immune system. In rare cases, this disease can be fatal. 

Each year in B.C., 10-25 people become sick from cryptococcosis and about 16% die from the disease. People over 50 years of age, those who take oral steroids, smokers, those with chronic lung disease and those with immunocompromising conditions (e.g. HIV infection, cancer, organ transplant) are at a higher risk of disease.

 

Many people will be exposed to the fungus sometime during their lives and most of these will not get sick. In people who become ill, symptoms appear many months after exposure. 

Symptoms of cryptococcal disease include:

  • Prolonged cough (lasting weeks or months)
  • Shortness of breath
  • Headache
  • Vomiting
  • Fever
  • Weight loss

If symptoms occur, the disease can cause pneumonia, meningitis, nodules in the lungs or brain, or skin infection.

People are advised to see their doctor if they live in or visit an area where the fungus can be found and experience these symptoms.

The infection is caused by breathing in Cryptococcus fungus. It is not transmitted from person to person or from animal to person. A person with cryptococcosis is not contagious.

Cryptococcus gattii infection is not easy to diagnose because the disease is rare, the combination of symptoms can be unusual and symptoms can be mild and last a long time before a patient seeks medical attention. 

People are advised to see their doctor if they experience symptoms such as those described above, especially if the symptoms persist or are severe. People should remind their doctor that they live in or visited an area where the fungus can be found.

Doctors can request tests for patients who show symptoms. They can test for Cryptococcus in blood, lung or spinal fluid samples. 

Tests are not performed on people without symptoms just to see if they have been exposed.

Treatment consists of 6-12 months of antifungal medication. In most cases the disease can be treated successfully. There is no vaccine to prevent cryptococcal disease.

If you are a smoker, you can decrease your risk of infection by quitting smoking. There are no other particular precautions that can be taken to avoid Cryptococcus gattii infection. You can, however, be alert for long lasting or severe symptoms and consult a doctor for early diagnosis and treatment.

 

Where is this fungus found?

  • Cryptococcus gattii is found naturally in the environment in B.C. and in other places around the world. It lives on trees and in the soil on the east coast of Vancouver Island and has occasionally been detected in the Vancouver Coastal and Fraser Health regions.

Why did the fungus appear in B.C.?

  • It is not clear why Cryptococcus gattii appeared in B.C. It may have been imported through air or on traveling people, vehicles or products or it may have always existed on Vancouver Island and increased in prevalence due to environmental change.

Is it safe to live on Vancouver Island or to travel there?

  • Yes. It is safe to travel to Vancouver Island. The risk of contracting the disease is very low and in almost all cases the disease can be treated. The benefits of outdoor exercise far outweigh the risks of cryptococcosis. All areas where the fungus has been found remain open to the public.

Are my pets at risk of infection?

  • Yes, some animals such as cats, dogs, ferrets and birds can become infected with Cryptococcus gattii. They can develop neurological signs (e.g. weakness, blindness, seizures), skin lumps and nasal discharge. The infection can be tested for and treated by a veterinarian. Treatment can be costly and long. Animals cannot transmit the infection to humans and humans cannot transmit it to animals.

Can I tell which trees contain the fungus?

  • No, you cannot tell which trees contain the fungus by looking at them. The fungus is tiny and cannot be seen with the naked eye. The trees that have the fungus growing on them do not look diseased. The fungus can only be identified by testing tree samples in a laboratory.

Should trees in my neighborhood be tested?

  • Testing of trees and soil has been done in a number of areas on Vancouver Island and in the Vancouver Coastal and Fraser Health regions to help determine the general distribution of the fungus. It is not possible or even useful to test trees in specific neighborhoods. The fungus could be present in an area even if some trees from that area test negative.

Is there anything I can do to protect my trees from the fungus?

  • No. There are no fungicides or other chemicals that can be applied to trees to protect them. Cutting down trees on private property is not recommended because it will not prevent your exposure to the fungus.


SOURCE: Cryptococcus Gattii ( )
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