Blastomycosis caused by the fungus Blastomyces dermatitidis has baffled physicians and medical research workers for years, and facts concerning the epidemiology of the disease still remain obscure. A satisfactory skin-test antigen has not been available for widespread population testing, so present knowledge of the distribution of the disease is formulated from case reports. The areas of high incidence in the United States appear to be the Mississippi and Ohio river basins, including Louisiana, Mississippi, Arkansas, Tennessee, Kentucky, West Virginia, Illinois, and Wisconsin; and North Carolina, a Central Atlantic state. Furcolow et al,1 in their Kentucky study, suggest that recognition of the disease was delayed in most cases and that many cases were unrecognized. He considered blastomycosis an important medical problem in the central United States.
Blastomycosis, like histoplasmosis, is limited geographically. The factors limiting the fungus to certain geographic areas are at present unknown. Blastomyces dermatitidis presumably grows in