New Developments in Blastomycosis.

Blastomyces dermatitidis, the etiologic agent of blastomycosis, is a thermally dimorphic fungus that grows as a filamentous mold in the environment and as budding yeast in human tissue. This pathogen is endemic to North America, particularly in the states bordering the Mississippi and Ohio rivers, the Great Lakes, and the St. Lawrence Seaway.