American histoplasmosis in developing countries with a special focus on patients with HIV: diagnosis, treatment, and prognosis

Histoplasmosis due to Histoplasma capsulatum var capsulatum is a frequent systemic fungal infection in the Americas. Diagnostic and therapeutic options differ between North and South America. Disseminated histoplasmosis is an AIDS-defining infection. Prognostic factors of potentially severe presentations must be evaluated in order to facilitate the initial therapeutic choice.Patients with HIV with disseminated infections presenting with severe pulmonary and renal impairment have a poor prognosis. Cutaneous presentations are more frequent in HIV patients in South America than in North America. A murine model has shown that South American isolates have a greater virulence that North American isolates. These differences are due in part to diagnostic delays in resource-poor countries.Direct examination of May-Grünwald-Giemsa-stained smears or tissues in suspected histoplasmosis is a simple means of confirming the diagnosis in resource-poor settings. Studies of prognostic factors should further refine indication criteria to guide first-line treatment choice between amphotericin B and itraconazole. The association of tuberculosis and histoplasmosis is frequent in HIV patients and presents diagnostic and therapeutic challenges that may be difficult to resolve in resource-poor settings. It is important that affordable generic drugs for treating histoplasmosis be made widely available in resource-poor countries.