Companies say the virus, known as Matcher.A, is less potent than the I Love You virus that ravaged computer systems last May, but it could pose a nuisance by overloading mail servers internationally.
"What is interesting about it is that it has a timer and continues to send out e-mails to everyone," said Eric Chien, head of antivirus research for Symantec. "Mail servers could become overwhelmed."
Chien said that so far Symantec has received roughly 30 reports of the virus from corporate customers.
British antivirus company Sophos said it has received about a dozen reports, but one customer based in France was forced to shut down its mail system. "It doesn't seem to be a vast epidemic," said Graham Cluley, head of virus research at Sophos. "But it is obviously a cause for concern."
The virus, which targets only Windows users, comes attached to an e-mail message with the subject "Matcher," disguised as a program that will find someone a romantic match. The e-mail has the message: "Want to find you love mates!!! Try this its cool... Looks and Attitude Maching to opposite sex."
The virus does not damage an infected computer but is designed to spread quickly. Written in Visual Basic and transformed into an executable file, it periodically sends itself to everyone in a victim's address book. During system boot it also displays the message "From: Bugger" in DOS.
Cluley said that with luck, most PC users will not be fooled by the incoherent e-mail. "We hope that because it doesn't look like a regular communication it won't spread that much."
Staff writer Will Knight reported from London.