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Histoplasmosis

• Histoplasmosis [his-toh-plaz-MOH-sis] is a fungal infection that varies in symptoms and seriousness.
• Histoplasmosis usually affects the lungs and causes a short-term, treatable lung infection. When it affects other parts of the body, it is called disseminated histoplasmosis. Disseminated histoplasmosis can be fatal.
• The histoplasmosis fungus lives in soil, especially soil that is enriched with bat or bird droppings.
• People get histoplasmosis when they breathe in dust that contains the fungus.
• Histoplasmosis is treatable with fungus-killing medicines.
• To prevent histoplasmosis: 1) avoid exposure to dust from soil that might be contaminated with bat or bird droppings, and 2) avoid disturbing accumulations of bat or bird droppings.

What is histoplasmosis?

Histoplasmosis is an infection that varies in symptoms and seriousness. It usually affects the lungs. When it affects other parts of the body, it is called disseminated histoplasmosis.

What is the infectious agent that causes histoplasmosis?

Histoplasmosis is caused by Histoplasma capsulatum, a fungus. The fungus produces spores that can be inhaled when they get into the air. Spores are hardy forms of the fungus that can live in the environment for a long time.

Where is histoplasmosis found?

The histoplasmosis fungus is found throughout the world. The fungus grows naturally in soil in some areas of the United States, mostly in the midwestern and southeastern states and along the Ohio and Mississippi River valleys. It thrives in soil that is enriched with bat or bird droppings.

How do people get histoplasmosis?

Histoplasmosis is spread through the air. If soil containing the histoplasmosis fungus is disturbed, the fungus spores get into the air. People can breathe in the spores and get histoplasmosis. The disease is not spread from person to person.

What are the signs and symptoms of histoplasmosis?

Most infected persons have no symptoms. When symptoms occur, they vary widely, depending on the form of the disease.

The lung infection can be short-term (acute) and relatively mild, or it can be long-term (chronic) and serious. Symptoms of the acute lung infection are tiredness, fever, chills, chest pains, and a dry cough. The chronic lung infection is like tuberculosis and occurs mostly in persons who already have lung disease. It can progress over months or years and can scar the lungs.

Disseminated histoplasmosis results in a variety of serious symptoms and can involve all body organs. The liver and spleen usually become enlarged, and sores in the mouth or gastrointestinal tract can develop. Disseminated histoplasmosis can be fatal.

How soon after exposure do symptoms appear?

Symptoms of acute disease usually appear in 5 to 18 days (usually 10 days) after exposure.

How is histoplasmosis diagnosed?

Diagnosis can be made by laboratory culture or a blood test. A skin test is available but is useful only for outbreak investigations, not for diagnosis.

Who is at risk for histoplasmosis?

Anyone can get histoplasmosis. Chronic lung infections are more common in males than in females, and particularly in persons with chronic lung disease. Disseminated histoplasmosis occurs most often in infants, young children, and persons with weakened immune systems, such as those with cancer or HIV infection.

What complications can result from histoplasmosis?

Acute histoplasmosis can keep getting worse or can become chronic. Acute histoplasmosis can also spread from the lungs to other organs and lead to the disseminated form of the disease, especially in persons with weakened immune systems.

What is the treatment for histoplasmosis?

Persons with mild disease usually get better on their own. Severe cases of acute histoplasmosis and all cases of chronic and disseminated disease are treated with fungus-killing medicines.

How common is histoplasmosis?

Infection with histoplasmosis is common, but the disease is rare. As many as 80 percent of persons living in U.S. areas where the fungus is common have a positive skin test, meaning they have had the infection in the past. However, most of these people do not have a history of histoplasmosis symptoms.

Is histoplasmosis an emerging infectious disease?

Yes. Histoplasmosis is on the rise, mainly because of the growing number of persons with weakened immune systems. These include persons with HIV infection, those who have had a bone marrow or organ transplant, and those receiving chemotherapy for cancer.

How can histoplasmosis be prevented?

• It is not practical to test or decontaminate all areas that are known to be or might be contaminated with the histoplasmosis fungus, but these steps can reduce the risk of exposure:
• Avoid areas where the fungus might be growing, especially areas with accumulations of bird or bat droppings. The fungus often grows around old chicken houses, in caves and other areas where bats live, and around starling and blackbird roosts.
• Avoid disturbing accumulations of bat or bird droppings, and minimize exposure to dust in potentially contaminated sites. Before stirring up the soil, spray the area with a mist of water.
• When working in high-risk areas, wear disposable clothing and a dust mask that covers the nose and mouth.

This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health-care provider. If you have questions about the disease described above, consult a health-care provider.

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