Blastomycosis is an infection that comes from breathing in fungus spores.
The Oneida County Health Department recently issued a notice that the county was seeing an increase in cases.
Blastomycosis—or blasto as it’s often referred to—is an uncommon, but potentially serious fungal infection.
In a ten-year period between 2011 and 2020, Wisconsin has averaged about 114 cases per year, according to Wisconsin Department of Health Services.
Northern Wisconsin counties including Lincoln, Iron, Vilas, and Forest are among those with the highest rates in the state.
Top 10 counties with highest average annual blastomycosis rates in WI (cases per 100,000 people):
| Menominee | 44.8 |
| Lincoln | 15.3 |
| Iron | 11.8 |
| Vilas | 9.7 |
| Sawyer | 7.8 |
| Forest | 7.5 |
| Marathon | 7.1 |
| Florence | 6.7 |
| Oneida | 6.6 |
| Washburn | 6.3 |
The Great Lakes region in general tends to see more cases than other parts of the U.S. Blastomyces, the fungus that cause blasto.
It is most commonly found in moist soil, riverbanks, and low swamp areas. The spores can become airborne when dirt is disturbed and then people breathe in those spores.
Dr. Erika Crockford is an Aspirus family medicine physician in Eagle River. She says it isn’t unusual to see cases pop up this time of year after the snow melts and soil becomes exposed.
“Most cases of blastomycosis are actually asymptomatic or people don't even know that they have it. You can have really mild symptoms as well, like a cough or a mild fever, and some people get sick enough that they need to be hospitalized. Usually that is a high fever, chills, cough, and they're usually coughing stuff up,” said Crockford.
Symptoms can include:
- Cough
- Fever
- Chills
- Muscle aches
- Joint pain
- Chest pain
Crockford says if someone has pneumonia that's not responding to antibiotics as they would expect, they test for blastomycosis.
“Usually, treatment means hospitalization. We need to give you antifungals, and it's hard to give antifungals through oral medication,” said Crockford.
Crockford says death from blastomycosis is rare and tends to be with people that are already immunocompromised.
It typically takes three to six weeks for symptoms to appear after getting exposed, though it can be months in some cases. This makes it harder to track where someone might have picked it up.
Some animals, including dogs, can get quite sick or die from blasto and while a person can’t get it from their pet, both could get exposed at the same time.
Symptoms in dogs include:
- Skin sores (especially on the face or paws)
- Coughing, Wheezing, shortness of breath
- Unexplained limping
- Difficulty seeing
- Loss of appetite or weight loss
“I think the big thing is just knowing that most people are not going to be affected by it. It tends to be pretty rare. Usually, your doctor is looking for it,” said Dr. Crockford. “If your symptoms are not getting any better, and if you notice that a pet has it and you start to have similar symptoms, it's definitely time to get checked out.”
Blasto can also cause skin lesions. Crockford says this would look like purple to gray, warty type lesions.
There is no vaccine for blastomycosis nor is there any publicly available tests to detect the fungus that causes it in the environment.
