Outbreak of rare fungal disease confirmed in paper mill workers in Michigan’s Upper Peninsula

Source of fungus has not been identified

At a magnification of 400X, this was a photomicrograph of a specimen, under phase contrast illumination, and processed using lactophenol cotton blue (LPCB) stain. The specimen was extracted from a patient with a case of blastomycosis, also referred to as North American blastomycosis, caused by the fungal organism, Blastomyces dermatitidis. In this view, a yeast form of the organism had been assumed. (CDC/ Dr. Hardin)

DELTA COUNTY, Mich. – Health officials in Michigan’s Upper Peninsula are investigating an outbreak of a rare fungal disease among paper mill workers.

On Feb. 28, 2023, the Public Health Delta and Menominee Counties was alerted to several atypical pneumonia infections in people who worked at the Escanaba Billerud Paper Mill.

Since then, officials have identified 35 (confirmed or probable) cases of Blastomycosis among mill workers. Another nine cases are awaiting test results.

Blastomycosis is an infection caused by a fungus called Blastomyces. The fungus grows in moist soil and decomposing matter. People can get sick from breathing in spores. The disease does not spread from person to person.

“The health and safety of our Escanaba employees has been and continues to be our first priority,” said Brian Peterson, Operations Vice President, Billerud Escanaba Mill. “Though no causal link to our mill has been confirmed, we are taking this matter very seriously and have taken a number of proactive steps.”

Officials have not yet determined the source of the fungus causing this outbreak. They said the fungus is common in the environment in the Upper Peninsula.

What is blastomycosis?

Blastomycosis is an infection caused by a fungus called Blastomyces.

According to the CDC, the fungus lives in moist soil and decomposing matter, like wood and leaves. It mainly lives in the midwestern, south-central, and southeastern states, particularly in areas surrounding the Ohio and Mississippi River valleys, the Great Lakes, and the Saint Lawrence River.

People can get blastomycosis after breathing in fungal spores from the air. Most people who breathe in the spores don’t get sick, but some will develop a fever and cough. The infection can be serious if it is not treated.

What are the symptoms of blastomycosis?

People who get sick from Blastomyces might experience the following symptoms:

  • Cough (sometimes with blood)
  • Fever
  • Chest pain
  • Difficulty breathing
  • Night sweats
  • Fatigue
  • Weight loss
  • Muscle aches
  • Joint pain

What is the treatment for blastomycosis?

Anyone experiencing symptoms of blastomycosis should contact their doctor. There is no vaccine that can prevent blastomycosis, but the disease can be treated with prescription antifungal medications. Treatment should be started as soon as possible after diagnosis.

What is the paper mill doing?

Health officials said that even though a source of infection has not been identified, the Escanaba Billerud Paper Mill has created a plan to prevent more illnesses.

The paper mill is expected to take the following steps:

  • Conducting extensive cleaning of common areas
  • Inspecting ventilation systems and filters
  • Testing raw materials coming into the mill
  • Retention of an industrial hygienist to assist with the investigation
  • Providing N95 masks to all employees
  • Requesting NIOSH perform a health hazard evaluation to study employees’ health and the safety of the community

About the Author:

Kayla is a Web Producer for ClickOnDetroit. Before she joined the team in 2018 she worked at WILX in Lansing as a digital producer.