A variant of the infamous Love Bug computer virus is said to be in circulation which, virus experts say, is much more destructive although it may not spread as quickly.

Computers at several large companies were infected late on yesterday, according to a spokesman at Californian anti-virus software company Trend Micro. With one casualty, all of its 5,000 computers were infected.

As with the Love Bug, only recipients running Microsoft's Outlook e-mail program are vulnerable. The new virus is carried in an email attachment but is not identifiable by its subject line as was its predecessor’s "I LOVE YOU". Instead, the subject line changes to a random word or phrase every time a computer is infected.

Says Symantec, which markets the best-selling Norton AntiVirus software: “Each time the virus spreads, it mutates itself to evade detection." The subject line of an infected e-mail starts with "FW" and also displays the name of a randomly chosen attachment from a previous e-mail from an infected computer. The infected email has an attachment with the same name, but ending in "vbs". Clicking on the attachment activates the virus which will then destroy most of the files on the hard drive. There is no danger if the attachment is not opened, say virus experts.

News source: BBC Online Business News (UK)