Many people who are infected with the fungus do not show any symptoms. In areas of the world where the fungus is very common in the environment, many people may have been infected withHistoplasma capsulatum without having any symptoms. If symptoms occur, they usually start within 3 to 17 days after being exposed to the fungus.

In people who develop disease, the most common symptoms are similar to those of pneumonia, and include: fever, chest pains, and a dry or nonproductive cough. Some people may also experience joint pain. If the disease is not treated, it can disseminate (spread) from the lungs to other organs.

The mild pulmonary (lung) form of histoplasmosis will generally resolve within about a month without treatment.
Prescription antifungal medications are needed to treat severe cases of acute histoplasmosis, and all cases of chronic or disseminated disease.  Itraconazole is one commonly used antifungal medication.  Treatment may continue for 3 to 12 months, depending on the severity of the disease and the immune status of the person.  Past infection can provide partial protection against severe disease if a person becomes re-infected later in life.

There is no vaccine to prevent histoplasmosis, and it is not always possible to prevent exposure to the fungus in areas where the fungus is endemic. However, you should avoid areas with accumulations of bird or bat droppings, especially if you have a weakened immune system.  Areas with accumulations of bird or bat droppings should be cleaned up by professional companies that specialize in the removal of hazardous waste.