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

The National Academies

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 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 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

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

Infectious Disease Videos

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What You Need to Know About Infectious Disease

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What do you know about infectious disease?

Which of the following diseases kills more children worldwide than any other infectious disease?

  • Correct!

    Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

  • Sorry, that’s incorrect.

    Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

  • Sorry, that’s incorrect.

    Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

  • Sorry, that’s incorrect.

    Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

  • Sorry, that’s incorrect.

    Lower respiratory tract infections (including pneumonia) kill more children worldwide than any other infectious disease. Together these diseases are the five leading causes of infectious disease worldwide, accounting for nearly one-fifth of all deaths.

Infectious Disease Defined

National Institute of Allergy and Infectious Diseases (NIAID)

Part of the U.S. Department of Health and Human Services and the National Institutes of Health, NIAID conducts and supports basic and applied research to better understand, treat, and ultimately prevent infectious, immunologic, and allergic diseases.

View our full glossary

National Academies Press

Search the National Academies Press website by selecting one of these related terms.