Online games like Mafia Wars and Mario Online have been growing in popularity. It is unlikely that the infected computer systems were used to access the internet. The virus was more likely introduced through gaming devices like portable Playstation (PSP) and smartphones. Many bored military personnel secretly bring in portable game consoles to pass the time during long duty hours. Or they may play online games on their iPhones and Androids smartphones. These gaming devices and smartphones can be recharged by plugging into the USB ports of computers.

WHO researchers say the H1N1 flu virus that swept the globe in 2009 has mutated, with the new strain appearing in Singapore and Australia.

The new virus has a genetic twist, making it resistant to drugs like Tamiflu and Relenza, the two mainstay drugs used to tackle the virus.

The World Health Organisation's influenza research group says more than 10 percent of H1N1 flu infection samples from Singapore, collected during the early months this year, showed mildly reduced sensitivity to the two drugs.