Read EVERY WORD of this article by Joe Barr including its very helpful user comments and burn it in your brain: you are not using a Microsoft product when using Linux, therefore you will not get a virus. This is possible because Linux was built CORRECTLY and because of its implementation of permissions.
“Microsoft designed Windows to enable outsiders to execute software on your system. The company justifies that design by saying it enriches the user experience if a Web site can do ‘cool’ things on your desktop. It should be clear by now that the only people being enriched by that design decision are those who make a buck providing additional security or repairing the damage to systems caused by it.”
Get out of the Microsoft mentality.