What is Blastomycosis?

Blastomycosis is caused by the dimorphic fungus, Blastomyces. The fungus lives in the environment, particularly in moist soil and decomposing matter such as wood and leaves.

Blastomyces is primarily found in the areas surrounding the Ohio and Mississippi River valleys and the Great Lakes region in the United States. It can also be found in central and eastern parts of Canada.

Blastomycosis develops after inhaling the fungal spores. Once in the lungs, at body temperature, the spores transform into yeast. In the lungs the yeast can be eliminated by the immune system, persist causing disease localized in the lungs, or spread through the lymphatics and bloodstream causing disseminated disease in many different organ systems.

Estimated Areas with Blastomycosis in the United States