Viruses

Viruses are germs that are even smaller than bacteria. They are so tiny that only a strong microscope can see them. Viruses are not quite like other living things. They need to get inside a cell to do anything.

How Viruses Make You Sick

When a virus gets in your body, it sneaks into your cells. It uses the cells to make more copies of itself. This can make you feel sick. Colds, flu, and chickenpox are all caused by viruses. Your body fights viruses with its immune system.

A chart shows different viruses and how big they are.
A chart shows different viruses and how big they are. (ViralZone, SIB Swiss Institute of Bioinformatics: Human virus relative size / Wikimedia Commons)

Staying Healthy

You can help keep viruses away. Wash your hands often with soap and water. Cover your mouth when you cough or sneeze. Try not to touch your face with dirty hands. Getting vaccines also helps protect you from many viruses.

Fun Facts

  • The word virus comes from a Latin word meaning poison.
  • Some viruses only make plants sick.
  • A sneeze can send virus drops flying across a room.

Did You Know?

A drop of seawater can have millions of viruses in it, but most do not harm people.