The city Department of Health confirmed Saturday that a Rikers Island inmate was tested for H1N1 flu, in the wake of Friday's closings of three more public schools.

Correctional officers on Rikers Island were encouraged to wear masks and visitors are off limits at the affected quarters at the Ann M. Kross Center. Corrections officials said that no new inmates will be sent to the area.

The sick male inmate, who arrived on April 18, complained of symptoms on Wednesday and was treated at Elmhurst Hospital in Queens.

A DOC spokesperson said the inmate's condition is not serious and that there are no other reported cases of H1N1 flu in city jails.

But the news that the unique flu virus, also known as swine flu, may have reached Rikers Island lead Norman Seabrook, president of the Correction Officers Benevolent Association, to ask for the immediate closing of Ann M. Kross Center at Rikers Island, which holds approximately 600 inmates.

"This is a very serious issue and it deserves the attention of everybody in the DOH and we should make sure that our members are treated just as fairly," said Seabrook on Friday. "They go home to their families, they go home to their children, and we have to make sure that this epidemic does not spread."

Seabrook wanted inmates and staff from the Kross Center transferred to other jails, including the recently re-opened facility in Brooklyn.

The DOC said the other inmates, correction officers and staff have been examined and the jail has been sanitized.

There are now six closed city schools that are scheduled to reopen on Friday, May 22 - five in Queens and one in Brooklyn. The schools are undergoing thorough cleanings, including the disinfection of desks, tables, floors and doors.

Only one closed school - I.S. 238 in Hollis, Queens - has confirmed cases of H1N1 flu. There, four students and one faculty member.

Assistant Principal Mitchell Wiener of I.S. 238 remains on a ventilator at Flushing Hospital, and he is suffering from kidney failure and a lung infection, according to his family. His case marks the most severe illness in the city since the first known cases of swine flu appeared in the five boroughs in late April.

His wife Bonnie, who teaches at the school, said school officials wanted to close last week when students first came forward with symptoms.

"My principal became concerned and he wanted to close to school and he wanted to alert the parents and the teachers because Mr. Joseph Gates is a man of compassion who cares for his staff, who cares for his students, who puts the health and safety of his students before any protocol," said Bonnie Wiener. "He was chastised by the Board of Education and some higher-up that he could set off a pattern."

But outgoing City Health Commissioner Thomas Frieden said a lot went into the decision to close the school.

"It's a judgment call. In this particular case, it was the first school to have large numbers of kids continuously out, day after day, and that is a different pattern," said Frieden. "We've seen other schools that have had large numbers out and then kids back in not large numbers. It has to be a school-by-school decision."

The other five schools saw unusually high absence rates, with dozens of students showing flu-like symptoms.

Officials say that in I.S. 318 in Williamsburg, Brooklyn, seen right, 275 students called out sick on Friday and teachers say another 80 students left early. Such widespread sickness may have lead officials to decide on more school closings.

"I think that what we've being doing all this week is carefully looking at attendance records at school, what the school nurses were telling us on how many kids they were seeing, and monitoring situations in schools with a difficult trigger to say, 'Okay, when does a school close?'" said Dr. Don Weiss of the DOH. "And if there's such a situation where kids are just coming in, they're leaving sick, and they can't function in school, then we really have to close the school."

Meanwhile, after enduring the brunt of the city's original H1N1 outbreak, students at St. Francis Prep High School in Fresh Meadows, Queens are tackling SAT tests in their own school today.

They were scheduled to take the big test on May 2, but it was postponed due to the school being closed a week after hundreds of people associated with the school experienced flu-like symptoms.

"We're kind of overreacting, it's just like other flus but people are over worried because it's different. So I think we can just keep clean, sanitize your hands and I don't think we should have anything to worry about," said one student.

"In a sense it was good because we didn't have school, but I was sad that all my friends were sick and in the hospital," said another.

Mayor Michael Bloomberg and Frieden have reminded New Yorkers over the last few days that H1N1 cases in the city have so far been no more severe than seasonal flu.

They reminded residents to wash their hands frequently and for sick New Yorkers to only seek medical attention for severe symptoms or if they have pre-existing medical conditions.

Centers for Disease Control officials have also downgraded its three-week-old travel warning to Mexico. The health agency says only people who are at high risk of flu complications should avoid traveling there.

Five people in the United States have died from H1N1 flu and more than 70 deaths have occurred worldwide.