Yes, Virus Scanners do require a knowledge of virus', but only if your making one. Thats what I say, learn about virus' and how to terminate and prevent them and make your own virus scanner, probably the best choice would be ASM. But thats only one step to security, you need a decent firewall to make sure your not hacked, or being hacked. Its also a good thing to use high security everywhere on the net, I've found trojans in pop-up's and all kinds of online things. Be afraid, there is so many precautions that must be taken, but linux is the most secure thing you'll find. Abandon Microsoft, they've let us down.
-Morag_Apocolypse