Learn About Blastomycosis

Key Facts

• Blastomyces is a fungus that grows in moist soil and rotting wood, and when inhaled, about half of the people exposed become sick with blastomycosis.
• Blastomycosis is a type of pneumonia caused by Blastomyces that is more likely to make people over 50, those who are living with a chronic lung disease or who have a weakened immune system seriously ill.
• Blastomycosis is treatable, but your healthcare provider must test for it.

How Blastomycosis Affects Your Body

You can get sick with blastomycosis by inhaling microscopic fungal spores, called Blastomyces that live in the environment in moist soil and decomposing plant matter like wood and leaves. They are released into the air by activities and weather events that disturb the soil or plant material. Once the inhaled spores enter your lungs, they are warmed up by your body temperature and turn into yeast. This yeast may stay in your lungs and cause fungal pneumonia or spread through your bloodstream to other parts of your body.

Blastomycosis is not contagious, meaning it is not spread from one person to the next. It used to be called Gilchrist disease or Chicago disease.

Who Is at Risk?

There are two types of risk factors to consider:

Risk of exposure:

• Anyone can get blastomycosis if you spend time in an area where Blastomyces lives and are doing outdoor activities that may disrupt areas where the fungal spores are accumulating, predominantly near lakes or rivers.  
  • Blastomyces lives in the Central and Eastern parts of the United States. Wisconsin and Minnesota typically record the highest number of illnesses.
  • Some hobbies place you at increased risk, such as hiking, camping, fishing or riding an all-terrain vehicle.
  • Some jobs place you at increased risk such as if you work at a construction or excavation site, or work in forestry.

Risk of infection:

• Certain individuals are more likely to become seriously ill from Blastomyces, including people who:
  • Have a weakened immune system due to pregnancy, HIV/AIDS, have had an organ transplant or are on certain long-term medications such as corticosteroids.
  • Are living with COPD or another chronic lung disease.
  • Are older than 50.
  • Have a racial or ethnic background including American Indian, Alaskan Native, Asian, Native Hawaiian or Pacific Islander.