A leading Hong Kong scientist said Thursday the flu virus in the special administrative region's current flu outbreak is no deadlier than past viruses, as health authorities kept more than half a million kindergarten and primary students at home as a precaution.

Yuen Kwok-yung and a panel of experts studied two flu patients who died during the outbreak - a 7-year-old boy and a 3-year-old girl - and found that the flu virus had not spread beyond their lungs, which suggested the virus was not exceptionally virulent.

"If it was a more virulent virus, we would be able to find the flu virus in other organs," Yuen told reporters.

The World Health Organization also said yesterday there was no reason for concern.

WHO spokesman Peter Cordingley called the Hong Kong outbreak "just regular seasonal flu."

"Hong Kong is a flu viruses' playground. It's such a congested city that the lines of transmission of the virus are always there," he said from Manila.

The outbreak has not been linked to bird flu, which has infected birds in Hong Kong.

Bird flu remains difficult for humans to catch, though scientists fear the virus that causes it could eventually mutate into a form that spreads easily among humans.

But late on Wednesday the Hong Kong government ordered all kindergartens, primary and special education schools closed for two weeks from Thursday.

This move was reminiscent of the measures taken during Hong Kong's outbreak of SARS (severe acute respiratory syndrome).

Nine students who arrived early yesterday at the Cho Yiu Catholic Primary School were greeted by school staff who took their temperatures and distributed masks. The students read picture books instead of attending class.

"Some classmates were sick but they still came to school. I'm worried they have spread the virus and more people will get sick," 11-year-old Wong Pui-shan said.

The closure in effect starts the Easter holiday for schools about a week in advance.

The move will affect nearly 560,000 students at 1,745 schools.

Hong Kong health officials have reported nine confirmed flu outbreaks and 65 suspected ones since March 6, mostly at schools, affecting more than 530 people in the territory of nearly 7 million. At least three children have died during the outbreaks, two of whom were confirmed to have the flu.

(Shanghai Daily March 14, 2008)