Michigan Officials Monitoring Large Outbreak of Fungal Infections Tied to Paper Mill

Public health officials are continuing to investigate and monitor a large outbreak of blastomycosis, a type of fungal infection that can become serious if not treated, tied to a paper mill in Michigan’s Upper Peninsula.

As of last Friday, the local agency leading the investigation — Public Health, Delta & Menominee Counties — has reported that more than 90 people have been potentially affected by the outbreak associated with the Billerud Paper Mill in Escanaba.

Specifically, there have been 19 confirmed cases, in addition to 74 probable cases in those with a positive antigen or antibody test, the agency said.

“Although the source of the infection has not been established, we continue to take this matter very seriously and are following recommendations from health and government officials and implementing numerous, proactive steps to protect the health and safety of our employees, contractors, and visitors,” Brian Peterson, vice president of operations for the paper mill, said in a statement in the health department announcement.

Importantly, the infection does not spread person-to-person, or between animals and people, the agency noted.

Blastomycosis is caused by a fungus that lives in moist soil and decomposing matter like wood and leaves, according to the CDC. The infection can occur after breathing in fungal spores. Symptoms include fever, cough, chest pain, difficulty breathing, night sweats, fatigue, weight loss, muscle aches, and joint pain. Though fatalities are rare, they can occur.

Public Health, Delta & Menominee Counties said that any individuals experiencing symptoms should contact their healthcare providers to discuss whether testing for blastomycosis is recommended.

The current outbreak appears to be the largest ever reported. Previously, a 2013 study published in Clinical Infectious Diseases, which examined a community outbreak of blastomycosis in Wisconsin, concluded in part that the 55-person outbreak was “the largest ever reported.” However, there have been other clusters of blastomycosis over the years, and exact case counts can prove elusive.

Cornelius Clancy, MD, director of the mycology research unit at the University of Pittsburgh School of Medicine, told MedPage Today that the current outbreak is indeed a large cluster and could potentially end up at the top of the list in terms of size.

Infections are “usually related or presumed to be related to some sort of common environmental source,” Clancy said. Oftentimes, infections arise in areas of construction or other disruption to the environment where the fungus is embedded, with the fungus becoming aerosolized into spores that are inhaled.

A common scenario is that additional cases of blastomycosis are identified after an affected individual initially thought to have bacterial pneumonia does not get better with normal antibiotic treatment, Clancy explained. It can take “relatively severe cases to draw everyone’s attention to the fact that cases are occurring.”

“It can cause severe disease even in people who don’t have known underlying medical conditions or immunosuppression,” he added. “And in people who do have other medical conditions … the risk of having a serious case is higher.”

However, unlike COVID-19 or other viral infections, a person is not going to travel to another area and transmit blastomycosis to others, he noted. “You’re going to have some sort of geographically condensed area where spores were dispersed,” he said.

Clancy stressed that it is important for healthcare providers in endemic areas to be aware of infections and keep blastomycosis in mind should they have patients with an unexplained clinical syndrome. That awareness is essential to testing for, diagnosing, and treating blastomycosis with antifungal medications when needed, he added.

“We are seeing more and more of these fungal infections, in general,” he said.

A spokesperson for Public Health, Delta & Menominee Counties declined MedPage Today‘s request for further comment on the matter, citing an ongoing investigation, but did note that an additional update is expected in the coming days.