Klez.H clocking up one infection every 300 emails A variant of the Klez virus has taken the crown as the biggest virus of all time, usurping last year`s SirCam outbreak and even the infamous Melissa and I Love You viruses. Statistics from antivirus firm MessageLabs found that the Klez.H variant overtook SirCam on Sunday, clocking up 775,000 copies. Full Story