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• Viruses are the smallest type of microbe, even smaller than bacteria.
• Viruses are really the bad guys of the microbe world. They don’t do anything that we would call good. (Only in the last few years have scientists come up with ways of making viruses do useful things for us…)
• Viruses are strange things that are somehow in between being alive and not alive. If they're floating around in the air or sitting on a doorknob, they do absolutely nothing. They're about as alive as a rock. But if they come into contact with a suitable plant or animal cell, they spring into action. They infect and take over the cell like pirates hijacking a ship.
• As a virus cannot reproduce without using another creatures’ cells to help it, some people are not convinced that viruses are really living things.
This virus gives you a cold!
This virus gives you flu!

• Unlike bacteria, viruses can’t move themselves around.
• But once a virus has got into another creature’s cell and used it to make new copies of itself, the cell bursts, and the new virus copies get shot off into the cells next door.
• There are thousands of types of virus that come in many shapes.
• Many have geometric shapes, like cut diamonds. Others are shaped like spiky eggs, skinny sticks or pieces of looped string. Some are more complicated and look like tiny spaceship landing pods.
• Viruses don’t have a nucleus. Their DNA
(genes) just floats around inside them.
They aren’t really even proper cells.
Draw this simple one:
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This is a picture taken with a microscope, showing a virus attacking a cell.
Don’t draw it – it’s too complicated.

• Viruses can be found almost everywhere!
They’re all over the planet, in soil, water and air, just waiting around for cells to infect.
• Viruses can infect every living thing.
However, they tend to be picky about what type of cells they infect. Plant viruses do not infect animal cells, for example.
This virus hangs around in soil, and infects wheat.
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When you have a cold and you sneeze, the cold virus is in the drops that shoot out of your nose and mouth! If it lands on someone else, it gets to work on them…
…so use a tissue!

• Even compared with bacteria (and your own cells), viruses are very small.
• Viruses don’t just attack cells of humans, other animals, and plants.
They even attack bacteria!
• If you lined up a million of them, they would only cover 1 mm in length!