Histoplasmosis is an infection caused by a fungus called Histoplasma capsulatum. It usually affects the lungs.

A person gets histoplasmosis by breathing in the spores of the fungus. It is not spread from one person to another. An infected person may feel generally sick and have a fever, cough, and chest pains. But many people who get infected do not have any symptoms.

People with a healthy immune system usually recover from a mild infection without treatment. But in people with a weak immune system, such as those with cancer or AIDS, histoplasmosis may spread beyond the lungs to other organs. This is called disseminated disease. People with a severe infection or disseminated disease are treated with antifungal medicines.