The pathologist Samuel Taylor Darling discovered in 1905 a new disease caused by a
previously not described microrganism that he named Histoplasma capsulatum based on an archaic
term for macrophages (Histo), its resemblance to protozoan parasites (plasma), and the apparent
presence of a surrounding capsule (capsulatum). However, it turned out that it was a fungus and not
encapsulated. In the last few decades, fungal infections have become more widespread due to the AIDS
epidemic end to the increase in immune compromised state of patients under chemotherapic treatment,
extensive use of antibiotics and organ transplants. In parallel with the developments of molecular
biology tools, our knowledge of the mechanism of virulence and host-parasite interactions have also
increased significantly. This chapter will highlight the major findings in these areas of investigation
focusing on the biology of the virulence determinants of H.capsulatum.
Keywords: Histoplasma, samuel taylor daring, virulence, phagocytic cells, conidia, yeast, hyphae, cell
wall, chitin, glucan, lectin, integrin
