<em>Histoplasma capsulatum</em> and <em>Histoplasmosis : </em> Current Concept for the Diagnosis

Histoplasmosis is a global deep mycosis caused by Histoplasma capsulatum (Hc), a dimorphic fungus. It exists on two main varieties Hc capsulatum and Hc duboisii that could be distinguished by their epidemiology, their clinical presentation, and the morphological aspect of the fungus at direct examination of the sample. Laboratory diagnosis of Hc remains a real challenge as it required experience and equipment. Through a general review of literature, the different diagnosis tools for Histoplasma sp. are analyzed, and strengths and weaknesses are pointed according to the context-based value. Isolation of Hc on culture is the gold standard for diagnosis of histoplasmosis. However, it remains less sensitive (sensitivity: up to 77%) and implies long time to result, which can be inappropriate or in adapted for an emergency diagnosis. So, nonculture methods as antigen testing, serology, and molecular biology become available and allow a rapid diagnosis. However, the optimal diagnostic method depends on many parameters as the very wide range of symptomatology, the immune status. Indeed, Ag detection is the best diagnosis tool for PHD (sensitivity: 92‚&#196;&#236;95%) and SCN histoplasmosis (sensitivity: 66%) and serology for the subacute/chronic form (sensitivity: 85‚&#196;&#236;93%). Thus, the clinico-biological dialog is essential, and histoplasmosis management includes an integrated medical approach.