ABSTRACT
Human infection with the pathogenic fungus Histoplasma capsularum poses a significant health risk to those who reside or have resided in the endemic region. This area encompasses the midwestern and southeastern United States and Central and South America. It is one of several endemic pathogenic fungi present in the Americas. Rough estimates of new infections with H. capsulatum within the United States range from 200,000 to 500,000 annually [I]. Infection is acquired via inhalation of microconidia or mycelial fragments into the alveoli and terminal bronchioles where they convert into the yeast phase [2]. It is this form that is responsible for clinical and pathological manifestations of the disease. The vast majority of primary cases of histoplasmosis (>95%) produce mild, influenza-like symptoms or are asymptomatic [3,4]. Infected individuals infrequently seek medical attention and if they do, rarely is histoplasmosis considered a possible explanation for their symptoms, even in the endemic region.
