April 26 (Bloomberg) -- At least eight students from a private school in New York are suspected of having swine flu, New York health officials said yesterday as teams of international investigators raced to determine how widely the potentially deadly virus has spread.

About 200 children from the 2,700-student St. Francis Preparatory School in Queens were absent last week with flu-like symptoms, said Thomas Frieden, commissioner for the New York City Department of Health and Mental Hygiene, at a press conference yesterday. All of the cases have been mild, lasting several days, and none of the children have been hospitalized, he said.

New York health officials will confirm today whether the suspected swine flu cases are linked to a new strain of the virus that may have killed at least 80 people and made more than 1,000 people ill in Mexico. That strain has spread to people in California, Texas and Kansas, where 11 cases, and no deaths, have been verified, the U.S. Centers for Disease Control and Prevention said yesterday.

“What we are concerned about is whether we might start to see more widespread transmission or serious illness,” said Frieden. “The city is very well prepared. We have been preparing for years at every level.”

The World Health Organization declared the epidemic “a public health emergency of international concern” yesterday after an emergency committee of the Geneva-based agency. The organization’s director-general, Margaret Chan, warned countries to be on the lookout for suspicious cases of respiratory disease that may be linked to the Mexico outbreak.

Schools, libraries and museums in Mexico have been closed and the government is handing out face masks. While the virus has pandemic potential because it is a new strain infecting people, it isn’t certain to cause a worldwide outbreak of deadly flu, Chan said.

Exposure Unknown

New York health officials said they don’t know how the students were exposed to the virus, though some students at the school traveled outside the U.S. during a recent spring break. They aren’t receiving special treatment, Frieden said.

New York health officials are also investigating 30 reported cases of possible flu at a day-care center in the Bronx and have received several calls from people in Manhattan who said they became ill after traveling to Mexico. None of those cases have been confirmed yet as swine flu.

People feeling ill shouldn’t go to the hospital or emergency room unless they are severely ill or have a pre- existing medical condition, Frieden said. In the area of Queens where the suspected cases have occurred, there has been an increase in hospital visits from concerned citizens, he said.

Precautionary Measures

People shouldn’t take any extra precautionary measures aside from washing their hands, staying home if they are ill and covering their coughs and sneezes, Frieden said. None of the children are being given Roche AG’s Tamiflu or GlaxoSmithKline Plc’s Relenza, he said. Both companies said their medicine appears to be effective against this strain of virus.

The last case of swine flu near New York was in 1976 in Fort Dix, New Jersey, Frieden said. With the right genetic composition, a new, deadly flu virus can spread extremely rapidly through human communities. The Spanish Flu pandemic of 1918 spread around the world, killing about 50 million people.

The department of health said it believes the students have swine flu because they tested positive for a form of influenza type A that didn’t match the H1 or H3 subtypes. The students tested were selected at random. Health officials have interviewed more than 100 of the ill students.

St. Francis canceled a scheduled reunion at the school this weekend and should be open on Monday, according to its Web site. The school is being disinfected over the weekend, New York health officials said.

To contact the reporter on this story: Shannon Pettypiece in New York at spettypiece@bloomberg.net

Last Updated: April 26, 2009 00:00 EDT