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Histoplasmosis is an infection caused by breathing in spores of a fungus often found in bird and bat droppings. Histoplasmosis is most commonly transmitted when these spores become airborne, often during cleanup or demolition projects.
Soil contaminated by bird or bat droppings also can transmit histoplasmosis, so farmers and landscapers are at a higher risk of the disease. In the United States, histoplasmosis most commonly occurs in the Mississippi and Ohio river valleys.
Causes of Histoplasmosis
Fungal spores can be released into the air when contaminated soil or droppings are disturbed. Breathing the spores may then lead to an infection.
The spores that cause this condition are commonly found in places where birds and bats have roosted, such as:
- chicken coops
- older barns
You can get histoplasmosis more than once. However, the first infection is generally the most severe. The fungus doesn’t spread from one person to another. It’s not contagious.
The most severe variety of histoplasmosis occurs primarily in infants and in people with compromised immune systems. Called disseminated histoplasmosis, this variety can affect nearly any part of your body, including your eyes, liver, central nervous system, skin and adrenal glands. If untreated, disseminated histoplasmosis is usually fatal.
Types of Histoplasmosis
Acute – Acute, or short-term, histoplasmosis is typically mild. It rarely leads to complications.
The Centers for Disease Control and Prevention (CDC) estimate that between 50 and 80 percent of people who live in areas where the fungus is common have been exposed (CDC). Many of them probably did not have any symptoms of infection.
Chronic – Chronic, or long-term, histoplasmosis occurs far less often than the acute form. In rare cases, it can spread throughout the body. This disseminated form of histoplasmosis is considered life-threatening, unless treated.
Widespread disease mainly occurs in people with impaired immune systems. In areas where the fungus is common, the CDC says it may occur in up to 25 percent of people with HIV (CDC).
Symptoms of Histoplasmosis
Several types of histoplasmosis exist. The mildest form produces no signs or symptoms, but severe infections can be life-threatening. When signs and symptoms do occur, they usually appear three to 17 days after exposure and may include:
- Muscle aches
- Dry cough
- Chest discomfort
In some people, histoplasmosis can also produce joint pain and a rash. People who have an underlying lung disease, such as emphysema, may develop a chronic form of histoplasmosis that can additionally feature weight loss and a cough that brings up blood. Symptoms of chronic histoplasmosis sometimes can mimic those of tuberculosis.
Causes of Histoplasmosis
If you have a mild infection, you probably won’t need treatment. Your doctor might just have you rest and take an over-the-counter medication for symptoms.
If you have trouble breathing or are infected for longer than one month, treatment may be necessary. You will usually be given an oral antifungal medication but may require IV treatment. The most commonly used drugs are:
- amphotericin B
If you have a severe infection, you might need to take your medication intravenously (through a vein). This is how the strongest medications are delivered. Some people may have to take antifungal medication for up to two years.