Marshfield Clinic Research Institute led lab testing into the country’s largest blastomycosis outbreak

Marshfield, WI (WFHR, WIRI, WXCO)

After a 2022-23 outbreak at Escanaba mill sickened 162 people and led to one death, The Marshfield Clinic Research Institute tested nearly 500 environmental samples during an investigation into the largest known blastomycosis outbreak in the United States.
An estimated 20% of workers at the paper mill in Michigan tested positive for blastomycosis.

In March 2023, a cluster of atypical pneumonia cases, many of which were attributed to mill workers at the Billerud paper mill in Escanaba, was reported to the local health department. Investigators from the National Institute for Occupational Safety and Health (NIOSH), working with public health partners, facilitated blastomycosis case-finding through a medical survey and conducted an environmental assessment

Blastomycosis is a rare infectious disease caused by inhalation of Blastomyces fungal spores from the environment. Blastomyces is found in moist soil or decaying wood and leaves, often near rivers and lakes. Blastomycosis incubates over a two-week to three-month period and pulmonary illness is most common, ranging from mild, respiratory symptoms to severe, potentially fatal pneumonia.
Blastomycosis does not spread from person to person.

Jennifer Meece, Ph.D., is the executive director of Marshfield Clinic Research Institute and has researched blastomycosis for more than 20 years, investigating outbreaks throughout the Midwest “Blastomycosis is difficult to diagnose because its symptoms often mimic other respiratory illnesses, like pneumonia, making it hard to distinguish clinically,” Meece said. “Diagnosis requires seeing the fungus in tissue samples through a culture or microscope. It’s important for patients to begin treatment with antifungal medication as soon as possible, and to attempt to find the source of the exposure to prevent others from inhaling the spores.”

First in U.S.

In addition to being the largest blastomycosis outbreak ever reported in the U.S., this was the first associated with a paper mill or other industrial worksite. The mill’s location along a riverway in a wooded environment is consistent with Blastomyces habitat. Blastomyces typically does not propagate indoors; the spores potentially entered the building through unfiltered ventilation systems, open doors, and caused the exposure over several months.

Marshfield Clinic Research Institute is the research arm of Marshfield Clinic and is the largest private medical research institute in Wisconsin. The institute was established in 1959, and currently employs 31 Ph.D. and M.D. scientists and 155 other staff. In addition, approximately 150 physicians and other health care professionals are engaged in medical research through the institute. Approximately 400 clinical trials are conducted annually along with research into medical issues important to the Midwest. For more information, visit the MCRI website

Links

For more information on fungal diseases, visit https://www.cdc.gov/fungal/index.html