Blastomycosis

Blastomycosis is an infection caused by the fungus Blastomyces. The fungus lives in moist soil and decaying wood and leaves. You can get blastomycosis when you breathe in air around dirt that has been disturbed. Pay special attention when dirt is:

• Near a water source and has been disturbed.
• Moved by gardening, camping, hunting, hiking, riding all-terrain vehicles, or clearing brush.
• Near an excavation or construction site.

The best way to avoid becoming very sick is to talk to your doctor when experiencing any symptoms. Illness can occur two to 15 weeks after breathing in the fungal spores.

Because no environmental testing is available to identify Blastomyces, you may want to avoid activities that disrupt dirt in wooded areas or at the water’s edge

Symptoms can include:

• Cough
• Fever
• Chills
• Muscle aches
• Joint pain
• Chest pain

The infection can spread to other parts of the body, such as the skin or bones.

People who smoke, have lung disease, or have weakened immune systems are more likely to become sick.

Blastomycosis is not spread from person to person.

People are usually treated with antifungal medicine. The medication needs to be taken for several months.

Antibiotics do not work against blastomycosis.

Sortable list of blastomycosis cases by average annual case rate, county, and 10-year case count, 2011-2020 

Understanding our data

What do these charts mean?

These dashboards display the occurrence of blastomycosis in Wisconsin residents during a 10-year period by county. Data in the map and chart represent the county where the person lived at the time of their diagnosis and may not represent where they were exposed to and became infected with Blastomyces.

Blastomycosis is an uncommon disease and yearly case count fluctuations in each county can be challenging to interpret. Therefore, we use 10 years’ worth of data to understand where Wisconsin residents are more likely to become ill with blastomycosis.

Nearly all people who recover from blastomycosis do not get it again, so the case counts represent individuals who became ill and tested positive for blastomycosis.

How do we measure this?

Data source(s): The Wisconsin Electronic Disease Surveillance System (WEDSS).

Population estimates: The United States Census Bureau county-level annual population estimates.

10-year case count: The cumulative number of residents diagnosed with blastomycosis and reported to public health during the 10-year period.

Average annual case rate: The cumulative 10-year case count for the county is divided by 10 and by the mid-decade estimated population for that county, and then multiplied by 100,000. This generates the average rate or number of people with blastomycosis each year during the 10-year period if there were 100,000 residents in that county.

Rates are a way to standardize and compare the frequency of disease occurrence among different size populations. Four out of five Wisconsin counties have less than 100,000 residents, while Milwaukee has over 900,000 residents. If two counties have the same number of people with blastomycosis, the county with the smaller population will have the greater rate of disease occurrence. This can be seen when comparing the county lists sorted by case rate and then by case count in the above table.

Data shown are subject to change. Some examples of corrections or updates that affect presented data include:

• Addition of delayed disease reports.
• Updating a patient’s address to a different county or state.