By Ethan Covey
The largest documented outbreak of blastomycosis in the United States took place at a Michigan paper mill from 2022 to 2023, and is the first such outbreak to occur in a largely indoor industrial setting. A total of 162 cases of blastomycosis were identified (MMWR Morb Mortal Wkly Rep 2025;73[5152]:1157-1162).
“Although occupational blastomycosis has been reported in outdoor workers in industries such as farming, construction and landscaping, this outbreak was unusual in that