BECAUSE of the geographic location of Pittsburgh, one might anticipate the existence of histoplasmosis. Not only are the city and environs situated between two areas in which there is a high incidence of skin-test reactions, namely, Maryland and Ohio, but also they are located at the convergence of three major rivers. Although the city proper is highly industrialized, typical rural areas are adjacent to the city limits. Clinicians in the area are well aware of the implications of the geographic location as related to histoplasmosis, but definite knowledge of incidence is lacking. Only a few positive skin reactions have been obtained in the area, and no active clinical case, to our knowledge, has been reported. With this in mind, we began to gather data among patients of the Children's Hospital.
Because the literature covering epidemiologic studies in histoplasmosis in the United States has been reviewed by Shaw, Howell, and Weiss,