Disease Fact Sheet Series:

What is histoplasmosis?

Histoplasmosis is an infection caused by a fungus called Histoplasma capsulatum. Approximately 10 cases are reported each year in Wisconsin.

What are the symptoms of histoplasmosis?

Many people infected with histoplasmosis do not become ill. When a person develops symptoms, it usually involves the lungs and is characterized by weakness, chills, fever, muscle aches, chest pains, and a dry cough. Chronic lung infections resemble tuberculosis and may progress over months or years.

Where is the fungus that causes histoplasmosis found?

Histoplasma capsulatum is found throughout the world including the United States. The fungus often grows in soil around chicken houses, areas harboring bats, caves, and under starling and blackbird roosts.

How is this fungus spread?
The fungus grows in soil contaminated with bird or bat droppings. It produces spores that can become airborne if the soiled is disturbed. If a person breathes in these spores, they may become infected. The disease cannot be spread from person-to-person.

Who gets histoplasmosis?

Everyone is susceptible to the fungus and may get the disease if exposed. Lung infection is more common among males than females, especially in individuals with an existing chronic lung condition. Acute, disseminated disease is frequently seen in individuals with a weakened immune system, such as those with AIDS or cancer.

How soon after an exposure does symptoms appear?

If symptoms occur, they may appear from 3 to 17 days after exposure, with the average around 10 days.

What is the treatment for histoplasmosis?

Specific antifungal medications can be prescribed by your physician to treat severe cases of acute histoplasmosis and all cases of chronic and disseminated disease. Mild cases of the disease usually resolve without treatment.

Does past infection with histoplasmosis make a person immune?

Past infection results in partial but not complete immunity against ill effects if reinfected.

What can be done to prevent the spread of histoplasmosis?

It is not practical to test or decontaminate all sites known or suspected to be contaminated with Histoplasma capsulatum. The following steps can be taken to minimize exposure to the fungus:

1. Avoid areas that may harbor the fungus, (e.g. areas with accumulation of bird or bat droppings).
2. Minimize exposure to dust by spraying with a mist of water before stirring up areas known or suspected to be contaminated with the fungus.
3. When working in areas known or suspected to be contaminated, wear disposable clothing, and a protective mask.

Contaminated sites can be treated with a formalin solution. Persons who apply formalin should be adequately trained in the use of personal protective equipment including respirators and gloves.

For more information, contact your
Local Public Health Department

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Last Revised: March 20, 2008