99.9999 percent of all virus' are due to vulnerabilities and 'features' in Microsoft operating system designs. The do not apply to UNIX-based systems. If 99.99999+ of the problems are MS based, and 0.00001- percent is UNIX based, it may not be a good use of your time to worry about the 0.00001- percent problem. You many have other things (I know we do and other clients agree) that there are better ways to spend your time and resources.