from the New Yorker Magazine:
A virus is nothing more than a few strands genetic material wrapped in a package of protein. They are so rudimentary that many scientists don't even consider them to be alive. In order to survive, since it can't function on it's own, it must attach itself to a cell and then throws a coup de tat, seizes control, marshalls the media, hires a propaganda minister and issues new currency. It's like a molecular game of Risk (the Parkers Bros. board game).