What is blastomycosis?
Blastomycosis is an infection caused by a fungus. This fungus grows as a mould in the environment and when tiny particles from the fungus are inhaled, they can settle in the lungs and change into a yeast. This can cause swelling and infection.
Blastomycosis has been found in Ontario, other provinces around the Great Lakes and in other countries around the world.
What are the symptoms of blastomycosis?
Blastomycosis usually starts in the lungs. About 50% of people infected do not become ill. If symptoms occur, they usually develop 21 to 106 days after exposure and can include:
- Fever/chills
- Cough
- Shortness of breath
- Chest pain
- Extreme fatigue
- Weight loss
- Night sweats
- Muscle aches/joint pain
- Skin sores, ulcers, warts, or bumps (if infection spreads to the skin)
- In severe cases, blastomycosis can spread from the lungs to other parts of the body, such as the skin, bones, joints, organs, brain, and spinal cord.
People with weakened immune systems are more at risk for severe disease, including death.
How is blastomycosis spread?
Blastomycosis is usually found in moist soil. It is more common near water, in rotting leaves, plants and soil, or in undisturbed places like under a deck, porch, house or shed. When contaminated ground is disturbed, tiny fungal particles can be released into the air. When the particles are breathed in, they can cause an infection in the lungs. If the lung infection is not treated, it can spread to other parts of the body.
Rarely, a blastomycosis skin infection can occur if the fungus gets into a cut or wound.
Blastomycosis cannot spread from person to person or from animals to people.
Who is at risk for blastomycosis?
Anyone who spends time in areas where the fungus is found is at risk for blastomycosis. People most at risk are those who spend time near lakes or rivers or do activities that disrupt soil. High risk activities include farming, forestry work, outdoor construction, hunting, harvesting, gardening, digging, hiking and camping.
Blastomycosis can also infect pets like cats and dogs who go outdoors.
How is blastomycosis treated?
If you develop symptoms, see a healthcare provider. The first symptoms can be like other respiratory illnesses. Tell your healthcare provider if you have done any outdoor activities to help them determine if you could have been exposed to blastomycosis. Early diagnosis and treatment help prevent severe infection and illness.
Treatment may include antifungal medication. The type and length of treatment will depend on how severe the symptoms are.
How is blastomycosis prevented?
There is no vaccine to prevent blastomycosis. There are currently no reliable methods to test soil for blastomycosis fungus.
To lower your risk:
- Avoid activities that can disrupt soil, like gardening, digging and yardwork.
- Wear a dust mask while doing these activities, especially when your face is near soil.
- Wear long sleeves, pants and closed footwear when spending time in the woods.
Where can I get more information about blastomycosis?
Contact the Communicable Disease Control (CDC) Program at 705-474-1400, or toll-free at 1-800-563-2808, ext. 5229 or email us at cdc@healthunit.ca.
References:
- Ministry of Health. (2022). Infectious Disease Protocol, Appendix 1: Blastomycosis
- Public Health Ontario. (2024). Blastomycosis
- National Collaborating Centre for Infectious Diseases. Blastomycosis
- U.S. Centers for Disease Control and Prevention. (2024). Blastomycosis Basics