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Overview of Viral Infections


The Manual's Editorial Staff

Last full review/revision Mar 2020| Content last modified Mar 2020
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A virus is a tiny living organism. Viruses are so small they can be seen only with the most powerful microscopes. That's why they're called microorganisms (micro means very small). Other common microorganisms include bacteria Introduction to Bacteremia, Sepsis, and Septic Shock Bacteremia, sepsis, severe sepsis, and septic shock are related: Bacteremia: Bacteria are present in the bloodstream. Bacteremia can result from a serious infection or from something as harmless... read more . Viruses are much smaller than bacteria.

Unlike bacteria, viruses can't reproduce on their own. So when viruses get into your body, they take over certain cells Cells Often thought of as the smallest unit of a living organism, a cell is made up of many even smaller parts, each with its own function. Human cells vary in size, but all are quite small. Even... read more 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.

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

  • Cultures (when doctors take a sample from your body and try to grow germs from it in a lab)

How do doctors treat viral infections?

How can I prevent viral infections?

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