What we know about blastomyces, the fungus that killed 1 & infected 100 at a Michigan paper mill

The fungus is found in Michigan but an infection is very, very rare

By Preetha Banerjee
Published: Monday 17 April 2023
People can get infected after inhaling spores of the fungus. Photo: iStock

Yet another rare fungal infection in humans made headlines last week, this time in the United States. At least one person died and around a 100 were confirmed or suspected to be infected, all linked to the paper mill where the outbreak started in January 2023.

In late February 2023, 15 employees of the Escanaba Billerud Paper Mill, a Sweden-based paper and packaging company, complained of “atypical” pneumonia, the Public Health Delta & Menominee Counties (PHDM), the public health department, noted. 

Since then, apart from the one fatality, 12 people have been hospitalised with the disease caused by blastomyces fungus, according to official sources. The plant has been sealed off; cleaning and investigation for the source of the fungus will be carried out over the next three weeks, news publication The New York Times reported. 

What do we know about this fungus?

The fungus of the genus blastomycosis is endemic to Michigan, but instances of it infecting people are extremely rare — in the last five years, the state has recorded only 26 cases a year, PHDM said March 9, 2023. 

The fungus is found in the moist soil and decomposing wood and leaves in the midwestern, south-central and southeastern states of the US, according to the Centers for Disease Control and Prevention (CDC). In these places, only 1-2 cases of blastomycosis is reported per 100,000 people. 

If disturbed, microscopic spores from the fungus can get dispersed in air and travel freely. Human beings can contract blastomycosis by inhaling the spores. “But most people who breathe in the spores don't actually get sick,” noted CDC. 

The disease causes fever, cough, breathing difficulty and muscle aches, the US public health research agency mentioned. During severe infection, which is rare, the disease can spread from the lungs to other organs, like the skin, bones and brain.

“Symptoms appear between three weeks to three months after exposure,” according to the NYT report. 

It is usually diagnosed through tests done on blood and urine samples or imaging work of lungs. Body fluid and tissue culture tests can also indicate the infection but the report may take up to a couple of weeks to be generated. 

There are antifungal medications that work on blastomyces but the course of the treatment is long – lasting between six months and a year, according to CDC. 

An industrial outbreak of the fungal infection has never been reported before although outbreaks linked to a common has been recorded earlier, CDC noted. “Common-source blastomycosis outbreaks often involve activities that disrupt soil such as construction or excavation or recreational activities near lakes or rivers such as hunting, fishing or camping.”

Later this month, the CDC will be conducting screening tests on urine samples from mill workers and their contacts to check for antigens against the disease and rule out exposure, NYT reported. 

The disease control agency hopes that the data will help narrow down testing sites at the plant and reveal the source of the fungus and other information. 

Subscribe to Daily Newsletter :

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.