The local administration has shut down three schools yesterday. Earlier, they had announced the closure of three schools on Thursday after an assistant principal of one of them was hospitalised in critical condition.

Though there have been only five confirmed cases of the Swine flu so far, the authorities were baffled by the large number of cases with flu-like symptoms found in the schools, mostly in the Queens suburb, which were closed.

Daniel Jernigan, head of epidemiology for the flu division of the CDC, said the agency was seeing widespread flu activity. "something we would not normally expect at this time of year." The number of people infected by the virus nationwide could be as high as 100,000, far more than just the 4,714 cases currently confirmed by the Center for Disease Control and Prevention, The New York Times quoted one federal official as saying.