The National Academies: What You Need To Know About Infectious Disease

The National Academies

What You Need To Know About Infectious Disease


Histoplasma capsulatum, a fungus that grows in soil and other material contaminated with bat or bird droppings, is the cause of histoplasmosis. When contaminated soil is disturbed, spores become airborne and can be inhaled. The spores cannot, however, be transmitted from one infected person to another. Found throughout the world, the fungus is endemic in some areas of the United States, primarily the Mississippi and Ohio River Valleys. It has been found in bird roosts, poultry house litter, caves, and areas where bats live.

In most cases, infection does not cause any symptoms. If symptoms do occur, they will appear between 3 and 17 days after exposure, with the average timeframe being 10 days. If acute respiratory illness occurs, it results in fever, chest pains, a dry cough, and an overall feeling of illness. A chest X-ray may reveal distinct patterns on the lungs. Chronic lung disease, which looks like tuberculosis, can gradually worsen over months or years. When organs other than the lungs are affected, the disease is called disseminated histoplasmosis, a form that can be fatal if not treated. People with AIDS, cancer, or compromised immune systems caused by other illnesses are at the highest risk for this form of the disease.

Mild forms of the disease rarely require treatment. In cases of acute histoplasmosis and in all cases of chronic and disseminated disease, antifungal medications are used. If re-infected, past infection typically provides partial protection from symptoms.

The best way to prevent the disease is to avoid places that might harbor the fungus, such as locations with accumulations of bat or bird droppings. If you must work in areas where the fungus might be present, consult the National Institute for Occupational Safety and Health’s publication Histoplasmosis—Protecting Workers at Risk or call the CDC at 1-800-CDC-INFO for safety precautions.


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What do you know about infectious disease?

True or False: Our bodies contain at least 10 times more human cells than bacterial cells.

  • Sorry, that’s incorrect.

    Our bodies contain at least 10 times more bacterial cells than human cells. 

  • Correct!

    Our bodies contain at least 10 times more bacterial cells than human cells. 

Infectious Disease Defined

Autoimmune Disease
A condition in which the immune system mistakenly attacks healthy tissue in the body.

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