A tenacious computer worm which has wriggled its way onto machines worldwide is set to evolve on April Fool's Day, becoming harder to exterminate but not expected to wreak havoc.

E-mail system of the Prime Minister's Office was under the grip of a computer virus for three months last year forcing officials to replace the software.

A computer virus attack that has infected more than 6.5 million Windows PCs this week is one of the worst in years, internet security firm F-Secure said on Friday.

Obama fever may have swept the world following the Democratic presidential candidate's historic election victory Tuesday. But now millions of computer users are under threat from an Obama virus, network security companies say.

The government approved a new genetic test for the flu virus on Tuesday that will allow labs across the country to identify flu strains within four hours instead of four days.