What is a virus?

A virus is a tiny living organism.

Unlike bacteria, viruses can't reproduce on their own. So when viruses get into your body, they take over certain cells and use structures in those cells to make more copies of the virus.

This usually damages and then kills the cell. However, some viruses can stay inside cells for a long time without killing them.

There are thousands of different viruses. Some viruses infect people. Other viruses infect only animals. Only a few viruses can infect both people and animals.

What is a viral infection?

A viral infection is a sickness caused by a virus. Viruses can get into your body through breathing air, having sex, touching something with viruses on it, or being bitten by a bug such as a mosquito or tick.

Viruses usually infect only one type of cell. For example, the virus that causes the common cold infects only cells in your nose, mouth, and throat.

When you get a virus, your white blood cells attack it. These cells also remember how to fight it if the same virus gets into your body again.

Many viruses make you sick shortly after you get them and then go away. Some viruses don't go away and can make you sick a long time after you get them (for example, HIV and herpesvirus).

Certain viruses change how your cells work, which can lead to cancer. For example, the hepatitis B and C viruses can lead to liver cancer.

How can doctors tell if I have a viral Infection?

Doctors can tell if you have certain common viral infections based on your symptoms.

They may also do blood tests or cultures, which is when doctors take a sample from your body and try to grow germs from it in a lab.

How do doctors treat viral infections?

Doctors can't usually do much to treat many viruses. They'll mainly suggest treatments for your symptoms to help you feel better.

How can I prevent viral infections?

Take good care of your health. For example, wash your hands often with soap and water, and practice safe sex. Additionally, listen to your doctor's recommendations.