At least one person has died and nearly 100 have been sickened in a rare fungal outbreak at a Michigan paper mill, health authorities said, prompting the mill to temporarily close while local and federal investigators try to determine the source.
An outbreak of myxomatosis has been escalating at the Billerud Paper Mill in Escanaba, Michigan, since February.
Local health authorities initially identified about 15 possible cases. By mid-April, that number had risen to 21 confirmed cases and 76 probable cases. 12 people were hospitalized and one person died.
All reported cases were among workers, contractors, or factory visitors.
Billerud, a Sweden-based paper and packaging company, said Thursday that it plans to close the plant for three weeks starting next week to perform deep cleaning, check ventilation systems, replace filters and test the various raw materials entering the plant, which employs about 830 people. Additional cleaning required large parts of the mill to be empty, she added.
“Identifying the source can be difficult because the Blastomyces fungus is endemic to the area,” the company said in a statement. “There has been no industrial outbreak of this type documented anywhere in the United States.”
Mycosis fungoides is an infection associated with the fungus Blastomyces, which grows in moist soil and decaying material, such as wood and leaves, and can be transmitted through the air if disturbed.
Fungal infections are rare. In 2019, the US Centers for Disease Control and Prevention reported 240 cases of mycosis fungoides.
On average over the past five years, only 26 cases have been reported across Michigan, according to the local health agency. However, the agency noted that Michigan’s Upper Peninsula is a known risk area for myxomatosis infection.
According to the Centers for Disease Control and Prevention, “blastomycosis remains poorly understood.” Mushrooms live mainly in the Midwestern, south central, and southeastern states of the United States, especially in areas around the Ohio and Mississippi River valleys, the Great Lakes, and the St. Lawrence River.
Most people who breathe in Blastomyces germs will not get sick. Symptoms include cough (sometimes with blood), fever, chest pain, difficulty breathing, night sweats, fatigue, weight loss, muscle aches, and joint pain. Symptoms appear between three weeks to three months after exposure. Onychomycosis can be treated with antifungal medications.
Authorities said the patients’ initial symptoms began in January and February.
A team led by the National Institute for Occupational Safety and Health visited the plant March 27 and 28 after a request from Bellrod, according to an April 7 letter from Marcia Stanton, the acting health scientist, which was reported by CBS.
The agency advised the company to make N95 masks available to reduce potential exposure and to check the ventilation system and air ducts for “evidence of water incursion and microbial growth” while investigations continued.
On Saturday, the CDC said in a statement that it plans to return to the plant in late April to offer urine Blastomyces antigen screening tests for possible exposure. Participation will be voluntary.
Investigators will use the test results and a questionnaire to “inform environmental sampling strategy,” the agency said, adding that the data may help narrow down test sites at the 2,000-acre mill.
“Our top priority now and always is to protect the health and safety of our employees and contractors who work at the Escanaba mill,” Billerud President and CEO Christoph Michalski said in a statement. “We care deeply about their well-being and do everything we can to protect them and to identify and treat the root cause of the fungal infections of onychomycosis.”
According to the Billerud website, Escanaba started making paper in 1911 as the Escanaba Pulp and Paper Company. Today, the factory produces graphic papers used in commercial printing, marketing materials, and labels and has the capacity to produce around 660,000 tons of paper annually.