A new computer worm tries to spread itself by e-mail by taking advantage of concerns over SARS.

The worm is officially called I-Worm Coronex (Kaspersky). It is disguised as a bulletin on severe acute respiratory syndrome.

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Spread of the Windows worm has so far been minimal. Computer security experts at Global Hauri rate it as a medium risk and those at Symantec Corp., McAfee Security and Sophos consider it a low risk.

The Coronex worm uses a variety of subject lines, messages and attachment names to entice users, including "Severe Acute Respiratory Syndrome," "SARS Virus" and "Virus Alert!"

"This new worm is currently not as harmful or widespread as top level threats Nimda, Klez or Slammer," said Global Hauri CEO Eric Kwan, "but it manipulates people by using a common psychological reaction to a very real biological health threat."

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The worm infects Windows 95, Windows 98, Windows NT, Windows 2000, Windows XP, and Windows Me. It does not affect Macintosh, OS/2, UNIX, or Linux systems.

If a computer is infected, the worm searches for e-mail addresses in the Windows address book and uses its own built-in mail program to spread itself.

The worm also changes the start page of Internet Explorer to a World Health Organization Web page on the SARS outbreak.

Computer security Web sites recommend users update their anti-virus protection. The sites also offer instructions on how to remove the worm.