Blastomycosis
A fungal infection from breathing in Blastomyces spores
Quick Facts
- Type: Fungal infection
- Source: Spores in moist soil and decaying wood
- Mainly affects: Lungs, sometimes skin and other organs
- Treatment: Antifungal medication
Overview
Blastomycosis is an infection caused by a fungus called Blastomyces, which lives in moist soil and in decomposing wood and leaves. People become infected by breathing in tiny fungal spores, usually after the soil is disturbed. It is not spread from person to person.
The infection most often affects the lungs, where it can cause a pneumonia-like illness, but it can also spread through the bloodstream to the skin, bones, and other organs. Blastomycosis is found mainly in certain regions, including areas around the Ohio and Mississippi River valleys and the Great Lakes in North America. Many people exposed to the fungus never get sick, but those who do can range from mild illness to serious infection that needs prompt treatment.
Symptoms
Symptoms often resemble those of pneumonia or the flu and may appear weeks to months after exposure.
- Cough, sometimes producing mucus or blood
- Fever, chills, and night sweats
- Chest pain and shortness of breath
- Fatigue and muscle or joint aches
- Unintended weight loss
- Skin sores or wart-like bumps if the infection spreads to the skin
Severe lung involvement can cause significant breathing difficulty, and widespread infection can be serious, especially in people with weakened immune systems. Severe shortness of breath needs urgent care.
Causes
Blastomycosis is caused by inhaling spores of the Blastomyces fungus.
- Environmental source: The fungus grows in damp soil, rotting wood, and leaf litter, particularly near rivers and lakes.
- Exposure activities: Activities that disturb soil, such as digging, farming, construction, hunting, camping, or other outdoor work and recreation, can release spores into the air.
- How infection starts: Once inhaled, the spores can grow in the warm environment of the lungs and cause infection.
The infection is not passed from one person to another.
Risk Factors
- Living in or visiting regions where the fungus is common, such as the Ohio and Mississippi River valleys and the Great Lakes area
- Outdoor activities that disturb soil, including farming, construction, hunting, and camping
- A weakened immune system from illness or medications
- Recent exposure near rivers, lakes, or wooded areas
Diagnosis
Because symptoms mimic other lung infections, diagnosis often requires specific testing:
- Imaging: Chest X-rays or CT scans to look at the lungs.
- Laboratory tests: Examining and culturing samples of sputum, tissue, or fluid to identify the fungus.
- Antigen and antibody tests: Urine or blood tests that detect signs of the infection.
- Biopsy: Sampling a skin sore or affected tissue when the infection has spread.
Telling your doctor about recent outdoor activities or travel to areas where the fungus is common helps point toward the diagnosis.
Treatment
Blastomycosis is treated with antifungal medication, and the choice and duration depend on severity.
- Mild to moderate disease: Oral antifungal medicine, often taken for several months.
- Severe or widespread disease: Stronger intravenous antifungal treatment in the hospital, followed by oral medication.
- People with weakened immune systems: May need longer or more intensive treatment and close monitoring.
- Supportive care: Oxygen and other support for serious lung involvement.
Completing the full course of medication is important to clear the infection and prevent relapse. Most people recover with appropriate treatment.
Prevention
There is no vaccine, and the fungus is hard to avoid completely in areas where it lives, but some steps may lower risk:
- If you have a weakened immune system, consider avoiding activities that heavily disturb soil in areas where the fungus is common
- Be aware of the risk during outdoor work or recreation near rivers, lakes, and wooded areas
- Seek medical care for a persistent cough or flu-like illness after such exposures, and mention the exposure to your doctor
When to See a Doctor
See a doctor if you have a cough, fever, chest pain, fatigue, or weight loss that does not improve, especially after outdoor activities in areas where blastomycosis occurs, or if you develop unexplained skin sores.
Seek urgent care for severe shortness of breath, coughing up blood, high fever, confusion, or rapidly worsening symptoms, particularly if you have a weakened immune system, as serious infection needs prompt treatment.
Frequently Asked Questions
How do you catch blastomycosis?
You catch it by breathing in spores of the Blastomyces fungus, which lives in moist soil and decaying wood, usually after the soil is disturbed by digging or outdoor activity. It is not spread from person to person.
Is blastomycosis contagious?
No. It does not spread from one person to another. People get it only by inhaling fungal spores from the environment, so being around someone with the infection is not a risk.
Where is blastomycosis found?
It is most common in parts of North America, particularly around the Ohio and Mississippi River valleys and the Great Lakes region. It tends to occur near rivers, lakes, and wooded areas where the fungus grows in damp soil.
How is it treated?
Blastomycosis is treated with antifungal medication. Mild to moderate cases use oral antifungal pills for several months, while severe or widespread infection may need intravenous treatment in the hospital first. Finishing the full course is important to prevent relapse.
When is blastomycosis serious?
It can be serious if it spreads widely or causes severe lung disease, and people with weakened immune systems are at higher risk. Seek urgent care for severe shortness of breath, coughing up blood, high fever, or rapidly worsening symptoms.
References
- Centers for Disease Control and Prevention (CDC). Blastomycosis.
- MedlinePlus, U.S. National Library of Medicine. Blastomycosis.
- Mayo Clinic. Fungal infections.
- National Institute of Allergy and Infectious Diseases (NIAID). Fungal diseases.