Allograft-Transmitted Histoplasma capsulatum Infection in a Solid Organ Transplant Recipient.

Histoplasma capsulatum is a dimorphic fungus known to be endemic to the Mississippi and Ohio River valleys of North America. Infection is the result of exposure to the microconidia of the mold phase of the organism, and the degree of exposure and immunocompetency of the host are thought to be important determinants in the severity of consequent illness [1]. In most patients, histoplasmosis manifests as a self-limited respiratory illness with protean complaints that include fever, dry cough, and fatigue. The more severe form of the disease, progressive disseminated histoplasmosis, is far less common and is usually seen in very young, elderly, and immunosuppressed patients. Unfortunately, the diagnosis requires a high level of suspicion and is often delayed. We describe a case of progressive disseminated histoplasmosis in a pediatric orthotopic heart transplant recipient from a nonendemic area whose disease was acquired from the donor allograft and whose diagnosis was delayed because of an incomplete donor history.