Internet experts have warned people to be wary of e-cards featuring moon cakes as some of them might contain viruses.

Although no specific infections have been identified so far this year, in the past the cards have been known to carry unwanted attachments.

Pan Yanyan, who works for Pricewaterhouse Coopers China, said she received a moon cake e-card last year that contained a virus.

"I was very attracted by the e-card on QQ (an online chat platform), but after I opened it many harmful pages popped up on my computer," she said.

Pan said she had to completely reformat her hard drive to get rid of the virus.

In recent years, a growing number of people have chosen to send "virtual" moon cakes to friends and family members to celebrate the Mid-Autumn Festival.

Websites that provide moon cake e-cards have become increasingly popular as this year's festival approaches.

However, the local Internet supervision authority has warned people to ensure their anti-virus software is up to date and run daily checks of their computers.

"Always scan files you receive over the Internet before you download them," an official with the Guangzhou Internet supervision bureau said.

According to the Beijing-based Jiangmin New Science and Technology Co Ltd, China's biggest antivirus software provider, a virus named "Trojan.QQ.boker," appeared in more than 10 forms during the Mid-Autumn Festival of 2005.

Last year, a worm transmitted via QQ had 17 varieties.

(China Daily September 14, 2007)