An acute respiratory infection caused by inhaling the spores of the fungus Histoplasma capsulatum , which is found in bird and bat droppings common along river valleys.
Causes, incidence, and risk factors
Histoplasmosis is caused by a fungus found in the Central and Eastern United States, Eastern Canada, Mexico, Central America, South America, Africa, and Southeast Asia. Most patients have no symptoms ( asymptomatic ) or experience a mild flu-like illness and recover uneventfully. Acute pulmonary histoplasmosis may occur in epidemics. Progressive and chronic disease can also occur, particularly amongst those with impaired immune systems, such as people with HIV. Risk factors include travel to or residence in the Central or Eastern United States near the great river valleys, exposure to the droppings of birds and bats, and having a compromised immune system.
Treatment
Treatment for acute pulmonary histoplasmosis is usually not necessary. Amphotericin B, an antifungal medication, may be given for severe cases. Treatment with Amphotericin B is given for 2 weeks to children under 2 years old because they are at risk for developing disseminated histoplasmosis . Other alternatives if therapy is needed include itraconazole and fluconazole.
Expectations (prognosis)
When severe and progressive, the illness may last for 1 to 6 months, but is rarely fatal. It can be a very serious illness in people with weak immune systems, such as those who have had bone marrow or solid organ transplants or those who have AIDS.
Complications
Histoplasmosis can spread to other organs through the bloodstream (dissemination). This is usually seen in infants, young children, and immunosuppressed patients. Acute histoplasmosis can progressively worsen or can become chronic histoplasmosis .
Calling your health care provider
Call your health care provider if symptoms which may indicate histoplasmosis occur, particularly if you have an immune disorder, have been recently exposed to bird or bat droppings, or if you are being treated for histoplasmosis and new symptoms develop.
Prevention
Avoiding travel to areas where this spore is found would prevent it (but this is not practical). Avoid bird or bat droppings if you are in one of these areas, especially if you are immunosuppressed .