Histoplasmosis is an infection caused by breathing in spores of a fungus often found in bird and bat droppings. The infection is most commonly spread when these spores are inhaled after taking to the air, such as during demolition or cleanup projects.
Soil contaminated by bird or bat droppings also can spread histoplasmosis, putting farmers and landscapers at a higher risk of the disease. In the United States, histoplasmosis commonly occurs in the Mississippi and Ohio River valleys, though it can occur in other areas, too. It also occurs in Africa, Asia, Australia, and in parts of Central and South America.
Most people with histoplasmosis never develop symptoms and aren't aware they're infected. But for some people — primarily infants and those with compromised immune systems — histoplasmosis can be serious. Treatments are available for even the most severe forms of histoplasmosis.
The mildest forms of histoplasmosis cause no signs or symptoms, but severe infections can be life-threatening. When signs and symptoms occur, they usually appear three to 17 days after exposure and can include:
Some people with histoplasmosis also get joint pain and a rash. People who have a lung disease, such as emphysema, can develop a chronic form of histoplasmosis.
Signs of chronic histoplasmosis can include weight loss and a bloody cough. The symptoms of chronic histoplasmosis sometimes mimic those of tuberculosis.
The most severe variety of histoplasmosis occurs primarily in infants and in people with compromised immune systems. Called disseminated histoplasmosis, it can affect nearly any part of your body, including your mouth, liver, central nervous system, skin and adrenal glands. If untreated, disseminated histoplasmosis is usually fatal.
Contact your doctor if you develop flu-like symptoms after being exposed to bird or bat droppings — especially if you have a weakened immune system.
Histoplasmosis is caused by the reproductive cells (spores) of the fungus Histoplasma capsulatum. They float into the air when dirt or other material is disturbed.
The fungus thrives in damp soil that's rich in organic material, especially the droppings from birds and bats. It's particularly common in chicken and pigeon coops, old barns, caves, and parks.
Histoplasmosis isn't contagious, so it can't be spread from person to person. If you've had histoplasmosis, you can get it again. However, if you do get it again, the illness will likely be milder the second time.
The chances of developing histoplasmosis symptoms increase with the number of spores you inhale. People more likely to be exposed include:
Children younger than age 2 and adults age 55 and older have weaker immune systems, so they're more likely to develop disseminated histoplasmosis — the most serious form of the disease. Other factors that can weaken your immune system include:
Histoplasmosis can cause a number of serious complications, even in otherwise healthy people. For infants, older adults and people with compromised immune systems, the potential problems are often life-threatening.
Complications can include:
It's difficult to prevent exposure to the fungus that causes histoplasmosis, especially in areas where the disease is widespread. But taking the following steps might help reduce the risk of infection:
Diagnosing histoplasmosis can be complicated, depending on what parts of your body are affected. While testing might not be necessary for mild cases of histoplasmosis, it can be crucial in treating life-threatening cases.
Your doctor may suggest searching for evidence of the disease in samples of:
Treatment usually isn't necessary if you have a mild case of histoplasmosis. But if your symptoms are severe or if you have the chronic or disseminated form of the disease, you'll likely need treatment with one or more antifungal drugs. If you have a severe form of the disease, you might need to continue to take medications for three months to a year.
You're likely to start by seeing your primary care provider, who might refer you to a specialist in infectious diseases. Depending on your symptoms and the severity of your infection, you might also see other doctors, such as a lung specialist (pulmonologist) or a heart specialist (cardiologist).
Make a list of:
For histoplasmosis, questions to ask your doctor include:
Your doctor is likely to ask you questions, including:
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