There is no reason for a Mac user to ever enable the root account. Macs ship with the root account disabled by default. You are confusing administrative privileges with root privileges. The first OS X virus was the OSX/Leap-A worm (a handy timeline on this site is useful to share with fanbois when they claim there is no malware on the mac). A low number compared to Windows although greater than Linux. Pre-OSX Macs had around 40 viruses in the wild. I don't use OS X much but I did have a virus once on a shared machine using System 6 (a long time ago). I have been using PCs since 1982 and have fallen victim to one virus and I am ashamed to say that I opened the script when not paying attention.

This is flawed though as it doesn't protect you against flaws in Web Forums/trusted sites that have been hacked. Just like on the PC social engineering is the biggest threat and the best defence is to think twice about anything untrusted. If you regularly exchange files with Windows through dual booting or another machine you have a choice: (1) if it's your own PC and you trust your security on it do nothing (2) if it's someone elses or untrusted then run Clam or some other scanner.

Sophos antivirus mac review macworld