Hong Kong's government on Thursday ordered all kindergartens and primary schools closed for two weeks after a dozen students tested positive for swine flu in the territory's first local cluster of cases.
Territory leader Donald Tsang said 12 students at a local secondary school tested positive for the virus and that authorities have not been able to immediately determine how they contracted the sickness, indicating it likely has spread locally within the community.
"We are unable to identify the source of infection. This means they are indigenous cases," Tsang told reporters after a three-hour urgent meeting with senior health and education officials. The new infections bring the total number of cases in the city to 60.
At least one of the infected students, a 16-year-old girl who tested positive late Wednesday, had not traveled overseas recently, according to a government statement. All the patients are in isolation in hospitals.
Tsang said schools will be closed starting Friday to deter the spread of the virus, as authorities shift their preparedness level from "containment" to "mitigation."
"If we don't suspend classes, transmission among students and the community will spread quickly," Tsang said.
Though the infections have been among secondary school students, Tsang said only kindergartens, primary schools and special education schools are being closed for now.
The closure came a day after Hong Kong confirmed the first domestic transmission of swine flu in a 55-year-old man. The man, who has no recent travel history, is believed to have caught the infection at a cocktail party from a 20 year-old man earlier confirmed with swine flu after returning from London. The closure affects nearly 510,640 students at 1,626 schools, according to enrollment figures from the 2008-2009 academic years.