HISTOPLASMOSISHistoplasma capsulatum is a dysmorphic fungus that dwells on earth in specific geographic locations.Its presence is favored by the droppings of bird and bats.The human infection is caused by the inhalation of a high quantity of spores.We describe the clinical course of a forty three year old immunocompetent male , geologist, who acquired the infection while visiting underground mines in Central America and Peru.Ninety (90%) percent of the Histoplasma spp infection are asymptomatic.The rest of the cases are manifested by pulmonary or non focalized infection.Its diagnosis is based on cutaneous reaction tests, the detection of antigens in blood or urine and also by direct visual identification of the agent in clinical samples or culture.These patients must be treated with itraconazole or amphotericin-B in accordance to its clinical seriousness.