ILOVEYOU Virus - ILOVEYOU Virus The subject line of the infamous ILOVEYOU virus entices e-mail recipients to open the e-mail and thereby activate the virus. The ILOVEYOU bug became the world's most prevalent and costly virus when it struck in May 2000. By the time the outbreak was finally brought under control, losses were estimated at $10 billion, and the Love Bug was said to have infected 1 in every 5 personal computers worldwide. Antiviral software attempts to filter out virus-infected e-mail before it can reach a recipient.