The National Academies

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

What You Need To Know About Infectious Disease

How Infection Works

Microbes occupy all of our body surfaces, including the skin, gut, and mucous membranes. Most don’t do us any harm—in fact, many help us survive. But there are certain bacteria, viruses, and other microbial life forms that can cause illness or even death. Here we learn the basics about microbes and the fascinating relationship we have with them.

Microbes & Humans

Microbes & Humans

A human body contains at least 10 times more bacterial cells than human ones.

Microbes and humans have evolved a complex relationship over thousands of years. Find out just how interconnected we are.

More about microbes & humans

Types of Microbes

Types of Microbes

There are five major categories of infectious agents. 

Viruses, bacteria, and fungi—oh my! Learn about the different microorganisms that are the source of infectious disease in people.

More about types of microbes

Encountering Microbes

Encountering Microbes

Microbes may be the earliest life forms on Earth.

People and microbes have always shared this planet. But changes in the way we live are affecting how and where we encounter microbes. Discover the impact of our modern way of life.

More about encountering microbes

How Pathogens Make Us Sick

How Pathogens Make Us Sick

Infection does not necessarily lead to disease.

Pathogens (microbes capable of causing disease) call our immune systems into action. Find out more about how the body responds to these tiny invaders.

More about how pathogens make us sick

Explore Other Topics

What do you know about infectious disease?

True or False: Antibiotics work by introducing an agent that resembles a disease-causing microbe, thus stimulating the body's immune system to recognize it as foreign, destroy it, and "remember" it, so that it can more easily identify and destroy any similar, disease-causing microbes that it later encounters.

  • Sorry, that’s incorrect.

    The above describes how vaccines work. Antibiotics work by either killing bacteria or stopping them from reproducing, allowing the body's natural defenses to eliminate the pathogens.

  • Correct!

    The above describes how vaccines work. Antibiotics work by either killing bacteria or stopping them from reproducing, allowing the body's natural defenses to eliminate the pathogens.

Infectious Disease Defined

White Blood Cell

A special type of cell that works as part of the immune system to defend the body against disease and infection.

View our full glossary

National Academies

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