ABSTRACT
Histoplasmosis is a mycosis of the reticuloendothelial system involving the lungs, spleen, kidneys, and other organ systems. The infection is cosmopolitan Cases have been reported from every continent save Antarctica. The areas of highest incidence are the US and Latin America and much of the information on acquired resistance derives from studies on subjects in these geographic areas. Animal serum incorporated into culture media inhibits the growth of many species of fungi. Such growth suppression is caused most often by serum transferrin which binds iron and makes it unavailable for utilization by microorganisms. Those pathogenetic events which attend subclinical or acute primary disease in humans are essentially unknown because such forms of disease are by definition mild, uncomplicated events whose histopathological appearance is not studied, but the early pathogenesis recorded in experimental infections can be inferred as representative.
