The New York City Health Department has recommended closing the three schools for one week after documenting unusually high levels of influenza-like illness.
A Health Department spokeswoman said that four students and a staff member have tested positive for swine flu at I.S. 238.
A spokeswoman for the principal's union told Eyewitness News that the assistant principal at I.S. 238 was critically ill. More than 50 students at the school also reported flu-like symptoms.
Mayor Michael Bloomberg said 241 students at I.S. 5 and 29 at P.S. 16 were either sick with flu-like symptoms or simply absent from school.
Sources have confirmed that the assistant principal is 56-year-old Mitch Weiner. He has been with the NYC Department of Education for 30 years as a teacher and assistant principal.
Weiner was being treated at Flushing Hospital, where he was listed in critical condition. The mayor said that he may have had pre-existing health problems. In many other swine flu cases that turned critical, patients had pre-existing conditions.
The Department of Education was also monitoring the situation at MS 74 (Nathaniel Hawthorne Middle School) in Bayside, Queens. Some children have also come down with flu like symptoms, officials said.
Mayor Bloomberg repeated that outbreak of H1N1 remains relatively small.
"Most people haven't come down with it. We're talking about 4,500 students in a city of 8.4 million," he said. "It may be that a lot of people have it but the symptoms are so minor that they don't know it, that's one of the things we'll be studying. There does not seem to be a lot of people outside of these few schools that report flu symptoms, no companies calling in saying half our employees are staying home."
New York City's first known cases of swine flu appeared in late April, when hundreds of teenagers at a Roman Catholic high school in Queens began falling ill following the return of several students from vacations in Mexico, where the outbreak began.
At first, the virus appeared to be moving at breakneck speed. An estimated 1,000 students, their relatives and staff at the St. Francis Preparatory School fell ill in a matter of days.
City health officials became aware of the outbreak on April 24. The school closed and health officials began bracing for more illnesses throughout the city.
But the outbreak then seemed to subside. Additional sporadic cases continued to be diagnosed, but the symptoms were nearly all mild. The sick children recovered in short order. St. Francis reopened after being closed for a week.
The middle school with the confirmed cases is two miles from St. Francis.
Health officials say New York state has 16 new cases of swine flu, bringing the total confirmed to 230.
Most of the cases have been mild, with the symptoms resembling those of seasonal flu - fever, cough, sore throat, body aches and chills.
For facts about influenza, and more information about swine flu, please visit the Health Department and CDC websites. Some specific resources:
From New York City Health Department
Facts about flu
From Centers for Disease Control and Prevention
General information about swine flu
Swine Flu Case Definitions
Swine Flu Infection Control and Patient Care
Preventing the Flu