Viruses are very simple microbes, they can't do much by themselves.  Viruses need a host, another living organism that gives them everything they need to work.  Viruses take any chance they can to find a host.  They get inside the host's cells and take it over.  Viruses use the host cells machinery to make lots of copies, so many that the cell bursts and infects other cells around it!  They can make more viruses very quickly - just one virus can turn into lots of viruses and make you sick!    

So how do viruses try to take over your body?  Click on the link to Find out more!