Blastomycosis is caused by a fungus, Blastomyces, that lives in the environment, especially in moist soil and decomposing matter like wood or leaves, according to the US Centers for Disease Control and Prevention. Nineteen of the cases linked with Escanaba Billerud Paper Mill have been confirmed by culture or microscope, and the other 74 are probable, meaning the person has symptoms of blastomycosis and a positive antigen or antibody test, the health department says. Nineteen of the cases linked with Escanaba Billerud Paper Mill have been confirmed by culture or microscope, and the other 74 are probable, meaning the person has symptoms of blastomycosis and a positive antigen or antibody test, the health department says