Fungal Outbreak Sickens 100 Workers at Michigan Paper Mill

The source of the fungal outbreak, which is not known to spread from person-to-person, has not yet been identified

Nearly 100 workers at a paper mill in Michigan have developed a severe type of fungal infection, known as blastomycosis, according to local health officials.

The Michigan Public Health Departments for Delta and Menominee Counties issued a press release last week, indicating that the fungal outbreak is under investigation after identifying a cluster of sickened employees at the Escanaba Billerud Paper Mill. This is believed to be the first known blastomycosis outbreak in an industrial setting.

Last month, at least 15 employees of the mill became sick with what doctors believed to be pneumonia. However, after the employees were hospitalized and failed to improve with the usual treatments, additional tests identified the cases as a  fungal infection known as blastomycosis.

To date, investigators have positively identified 19 cases as blastomycosis through fungal cultures or verification via microscope. Another 74 employees have since become ill with similar symptoms, but those cases have not yet been confirmed as blastomycosis.

So far, about a dozen employees have been hospitalized as a result of the outbreak. One employee required hospitalization for several weeks.

Blastomycosis Fungal Infections

Blastomycosis is caused by the fungus Blastomyces, which primarily lives in moist soil and decomposing organic matter, like wood and leaves. The fungus can spread through inhalation of spores, but is not spread by human-to-human contact or animal-to-human contact.

Blastomyces is typically found in the areas surrounding the Great Lakes, Ohio, Mississippi, and Saint Lawrence Rivers. Officials said there has never been a documented industrial outbreak of blastomycosis anywhere in the United States.

Symptoms of blastomycosis include fever, cough, chest pain, fatigue, muscle aches, and joint pain. The infection can spread to the lungs and other organs. People with weakened immune systems may experience severe symptoms.

Anti-fungal medications are used to treat the infections, but blastomycosis infections often require multiple courses of treatment across nearly a year.

The U.S. typically experiences about two cases of the fungal infection per 100,000 people every year. Fatalities from blastomycosis are rare, with roughly 1,200 deaths occurring in the U.S. from 1990 to 2010.

Fungal Outbreak Investigation Status

The source of the fungal outbreak has not been determined, however the mill and health officials are continuing to investigate the outbreak.

The outbreak has raised some concerns, since blastomycosis is not known to spread from person to person. Investigators speculate those hit by the outbreak may have been in contact with materials that contain the fungal spores. Those spores may continue to pose a threat until the source is found and removed.

In the meantime, the mill has implemented recommendations from health experts in order to prevent the continuing spread of the outbreak, including testing raw materials, providing N95 masks to employees, conducting deep cleanings, and keeping an industrial hygienist on retainer.

More than 800 people are employed at the mill, which produces 730,000 tons of paper annually.

Local health officials recommend anyone experiencing any symptoms should contact their doctor for evaluation and testing.