Is Blastomycosis contagious?

Blastomycosis is not contagious and cannot be spread from person to person or from animals to humans. It is a fungal infection caused by inhaling spores from the environment, meaning you cannot contract Blastomycosis through physical contact, respiratory droplets, or social interaction with someone who is ill.

What causes Blastomycosis?

Blastomycosis is caused by the fungus Blastomyces dermatitidis (or occasionally B. gilchristii). This fungus thrives in moist soil, decomposing organic matter like wood and leaves, and areas near waterways. When the soil is disturbed—through activities like gardening, construction, or hiking—the fungal spores become airborne and are inhaled into the lungs, where they can cause an infection.

Why is there confusion about contagion?

Because Blastomycosis often causes respiratory symptoms like cough, fever, and chest pain, people frequently assume it spreads like the flu or a cold. It is important to clarify that while the symptoms may mimic other infectious diseases, the source is strictly environmental. There is zero risk of transmission to family members, caregivers, or friends when living with or caring for an individual diagnosed with Blastomycosis.

Where is the risk of contracting Blastomycosis highest?

The risk of developing Blastomycosis is tied to specific geographic regions, primarily the Ohio and Mississippi River valleys, the Great Lakes region, and parts of Canada. Infection risk factors include:

• Proximity to stagnant water or riverbanks.


• Occupations or hobbies involving soil disruption (e.g., landscaping, clearing brush).


• Living in endemic regions during warm, moist months.


• Underlying immune system suppression, which may increase the severity of the infection.

Next steps

• Consult an infectious disease specialist if you suspect symptoms after visiting an endemic area.


• Connect with the 27 members of the Blastomycosis community on DiseaseMaps.org for peer support.


• Ensure your physician is aware of your travel or work history in high-risk geographic areas.

Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Blastomycosis Overview.


• Centers for Disease Control and Prevention (CDC): Blastomycosis (Blastomyces) Statistics and Risk.


• National Library of Medicine (PubMed): Clinical Manifestations and Epidemiology of Blastomycosis.


• Orphanet: Rare Disease Database for Fungal Infections.