For ages, Mac users have lorded over us poor Windows users with the fact that viruses did not hit Macs. How often have I had to sit through hours of cleaning viruses from my PC or plain having to format and reinstall Windows. Well, the era of the virus-free Mac has ended.

In a major development, security experts are cautioning about what they call the first-ever virus to infect the Mac OS X, the version of the operating system that has shipped with every Mac sold since 2001.

Until now, the OS has been untouched by the seemingly endless wave of Trojans that have sprung forth on the Internet over the years. Now things are changing. Apple's growing market share and adoption of same microprocessors used in machines running Windows are making Macs more vulnerable to virus attacks. Apple was jolted from its stratified atmosphere when a security researcher found no less than seven showstopper bugs for the OS.