By Henry Goldman
Last Updated: May 15, 2009 00:00 EDT

May 15 (Bloomberg) — An assistant principal was hospitalized in critical condition and three New York City public schools shut in a renewed outbreak of swine flu that first sickened hundreds of residents about three weeks ago.

“Unusually high levels” of flu-like illness in the schools triggered the closures, Mayor Michael Bloomberg said last evening at a City Hall news conference. The male assistant principal at Intermediate School 238 in Jamaica, in the city borough of Queens, where more than 50 students have been sent home sick, may have had a pre-existing condition that worsened his illness, Bloomberg said.

New York City was the first area in the U.S. last month to report more than a dozen cases of swine flu that has now reached 34 countries and sickened more than 6,500 people worldwide, according to the World Health Organization. City health authorities said May 1 they would test only those New Yorkers seriously ill with flu-like symptoms because most local cases of the new influenza, known as H1N1, were no more severe than seasonal flu. At the time, Bloomberg said more than 1,000 people in the city may have been infected with the virus.

“I know that many will find this information troubling, but information I’ve always thought is the best antidote to anxiety and we will continue to provide New Yorkers with clear, accurate and timely information as we have it,” Bloomberg said last night. “By taking common sense precautions and not by overreacting we will get through this together.”

In addition to IS 238, or the Susan B. Anthony School, the shut schools are Public School 16Q in Corona, Queens, where 29 students were documented with flu-like symptoms, and IS 5Q, the Walter Crowley Intermediate School in Elmhurst, Queens, where 241 students were reported absent.

‘Unusually High’

“We have been carefully monitoring the H1N1 virus, and we’re taking this action today because there are unusually high levels of flu-like illnesses at three public schools,” Bloomberg said at City Hall, where he was joined by Governor David Paterson and city schools Chancellor Joel Klein.

“This is the best procedure: to close these three schools for public safety and for the continued safety of the families involved,” Paterson said.

A total of 4,500 students attend the three schools. The earliest date the schools may reopen is May 22 under the order put in place after health officials discovered the influenza symptoms. Bloomberg said H1N1 has been documented in the assistant principal and four students.

Flu Symptoms

Symptoms of H1N1 include fever, cough, body aches, headaches, chills, fatigue, sore throat and sometimes diarrhea and nausea. Bloomberg advised New Yorkers to go to the doctor if they have trouble breathing but stay home if it’s not severe for at least 24 hours, and to cover mouths when coughing or sneezing.

“While the symptoms of H1N1 flu seem to resemble those of seasonal flu, the H1N1 virus appears to spread rapidly so we’re closing these schools in order to slow transmission,” Bloomberg said.