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

What You Need To Know About Infectious Disease

How Infection Works

Types of Microbes

The microorganisms, or microbes, that can cause disease come in different forms. Viruses and bacteria are probably the most familiar because we hear so much about them. But fungi, protozoa, and helminths are also big players in the story of infectious disease. Learn more about each of these five main categories, as well as a recently discovered one: prions.

Viruses

Viruses

Viruses are unable to reproduce until they invade and commandeer living cells.

Influenza, measles, and the common cold are just some of the diseases caused by viruses. What is a virus and how is it different from other microbes?

More about viruses

Bacteria

Bacteria

Bacteria come in three shapes: spherical, rodlike, and curved.

Bacteria are single-celled organisms that have been around for billions of years. Discover their important characteristics.

More about bacteria

Other Microbes

Other Microbes

Bread mold and hookworm, both infectious agents, are neither bacteria nor viruses.

Viruses and bacteria may be the most recognizable of the microbes that can cause infectious disease. But there are several other varieties. Learn about them here.

More about other microbes

Explore Other Topics

What do you know about infectious disease?

How many people in the United States die from flu-related complications each year?

  • Sorry, that’s incorrect.

    About 36,000 people die from flu-related complications each year in the United States. More than 200,000 are hospitalized.

  • Correct!

    About 36,000 people die from flu-related complications each year in the United States. More than 200,000 are hospitalized.

  • Sorry, that’s incorrect.

    About 36,000 people die from flu-related complications each year in the United States. More than 200,000 are hospitalized.

Infectious Disease Defined

Disease

Any abnormal condition  that affects all or part of an organism, resulting in symptoms such as pain or loss of function.

View our full glossary

National Academies

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