People catch blastomycosis the same way dogs do: by breathing in spores from the environment. About half of infected people never feel sick. In the rest, it usually looks like a pneumonia that doesn’t go away.
Symptoms
Symptoms start 3 weeks to 3 months after exposure and can include:
- Fever, cough and shortness of breath
- Night sweats and tiredness
- Muscle aches and joint pain
- Weight loss
- Chest, rib or back pain
- Skin sores: raised bumps, blisters or ulcers
In severe cases it spreads to the skin, bones, joints and brain, or causes acute respiratory distress syndrome (ARDS).
Who is at higher risk
- People who disturb soil outdoors: forestry and construction workers, landscapers, hunters, anglers and campers.
- People with weakened immune systems, who are more likely to get severely ill: advanced HIV, organ transplants, steroids or TNF-inhibitor medicines, and pregnancy.
Healthy people get seriously ill too. In the 2026 Albany study, 57% of patients had no underlying health condition and 87% were hospitalized.
When to bring it up with your doctor
The CDC suggests testing when someone has pneumonia symptoms that don’t improve with antibiotics, new skin sores, or a link to a known outbreak, after time in an area where the fungus may live. If your dog has been diagnosed with blastomycosis, say so: you may have shared the same exposure.
Testing and treatment
- Tests: urine antigen tests (results in a few days), fungal culture (can take a couple of weeks), tissue samples and PCR.
- Treatment: antifungal medicine, usually itraconazole for mild to moderate illness and amphotericin B for severe illness, typically for 6 to 12 months.
- Outcomes: most people recover with treatment, but 8–10% of hospitalized patients die each year in the U.S.
There is no vaccine. See Prevention for ways to lower your risk.
Blasto Awareness shares public information for awareness only. It is not medical advice. Talk to your doctor about your symptoms. Sources: CDC; Ramirez et al., Emerging Infectious Diseases, 2026. Full list on the Sources page.