Shenzhen's tourism bureau warned local travelers who are planning to travel to Japan not to eat raw seafood after a record outbreak of the highly contagious norovirus infected more than 3 million people in that country.

A spokesman for the bureau yesterday said there is no vaccine against the virus, and advised travelers to wash their hands carefully before eating and after using the toilet.

"Japan has been hit by gastroenteritis caused by norovirus infection recently. The epidemic that infected tens of thousands people is the most serious one during the past 25 years," the Chinese Foreign Ministry said on its Web site Monday.

"To protect themselves from infection, Chinese citizens who visit Japan should try to avoid eating raw seafood during their journey," the ministry said.

Norovirus is known to cause gastroenteritis that brings stomach pain, severe diarrhea and vomiting.

Japan is one of the most popular destinations for Shenzheners during the New Year and Spring Festival holidays.

More than 3 million people in the country are thought to have been infected by norovirus, the highest since data was first collected in 1989, according to Japan's national institute of infectious diseases.

The institute is concerned that the outbreak may show "the largest ever spread."

The virus is typically transmitted by eating raw seafood and also from human to human by substances excreted or vomited.

A sales manager surnamed Ma with China Travel Service Shenzhen Co. Ltd. said there had been no cancellations by members of tour groups scheduled to visit Japan during the holiday.

"Signing up for a Japan trip for the New Year holiday was closed last weekend, and we are now arranging package tours for the Spring Festival in February this year," Ma said.

He admitted travelers will have the chance to eat raw oysters and other seafood in Japan, which is famous for sashimi, but insisted it is safe for the customers.

"Several dozens of tourists who joined our package tours to Japan came back this week and none of them was infected," he said.

There are many restaurants in Shenzhen that serve sashimi. Many restaurants serving Japanese cuisine said a very small amount of the seafood was imported from Japan and business has not been affected so far.

Norovirus has caused mass infections in other countries, including the United States, where hundreds of passengers on a cruise ship fell ill in two separate incidents in November and early December.

Editor: Donald