The blastomycosis outbreak being investigated in Waupaca County, Wisconsin has grown to 18 confirmed cases, up five during the past week.

The Wisconsin Division of Public Health puts the number of probable cases at 13.

Chest X-ray demonstrates lung infiltrates due to Blastomycosis/CDC
Chest X-ray demonstrates lung infiltrates due to Blastomycosis/CDC

They continue to advise the public who visited the Little Wolf River since Memorial Day weekend (May 23-25, 2015), they may have been exposed to the fungus that causes blastomycosis. If you develop symptoms including cough, fever, chills, muscle aches, joint pain or chest pain, visit your health care provider.

Illness may develop 2-15 weeks after exposure to the fungus. Because of the long period of time from exposure until illness onset, we expect to see additional cases of blastomycosis reported.

A symptomatic blastomycosis infection (50% of cases) usually presents as a flu-like illness with fever, chills, productive cough, myalgia, arthralgia and pleuritic chest pain.

Health officials note that the investigation is ongoing and the number of cases may increase.

Robert Herriman is a microbiologist and the Editor-in-Chief of Outbreak News Today

Follow @bactiman63