Students were welcomed back to St. Francis Preparatory School on Monday as if they'd been on spring break, but they couldn't help but be reminded of the reason it was closed.

Swine flu sickened perhaps as many as 1,000 people associated with the Queens high school. It had 45 confirmed cases.

"I'm feeling great now," said Ivy Buchelli, 16, who said swine flu was confirmed as the reason she had a fever, chills and body aches. "After the long break, I'm glad to see everyone else and how they're doing."

"I'm just hoping the school's clean," she added.

Fellow junior Paulina Janowiec, 17, said she also had been diagnosed with swine flu.

"It's a little nerve-racking, being back in school, knowing that there was a swine flu outbreak in school," she said. "But it's good to be back."

Despite their illnesses, both girls kept up with her homework through the school's Web site.

Green signs on the school's doors welcomed the students back.

Meanwhile, Mayor Michael Bloomberg said Monday that New York City has 73 confirmed and six probable cases of swine flu. That's 11 more confirmed cases than the city reported on Sunday.

Of the 79 cases, the mayor says, three have no link to Mexico or St. Francis Prep.

Click here for more developments.

Even as St. Francis reopened, the virus continued to spread, leading to newly confirmed infections and school closures around New York and in other states.

Health officials in Syracuse said Sunday that that city's Ed Smith Elementary School would close for a week because of a probable case of swine flu involving a student with a connection to St. Francis. That brings the total number of "probable or confirmed" cases of the illness outside of New York City to 17, according to state health officials.

The Deer Park Union Free School District on Long Island announced Saturday it was closing until May 10 because three students likely have swine flu. The students don't appear to have any connection to St. Francis and haven't recently traveled to Mexico, where the swine flu may have originated, according to a county health commissioner.

The majority of the flu cases in the state have been connected to St. Francis, New York City health officials said. A group of students from the prep school fell ill after traveling to Mexico for spring break.

On Saturday, the city's health department said there was one confirmed case not associated with the school.

Meanwhile, New Mexico officials announced Sunday that 14 schools in four towns were being closed for at least a week after the state's first swine flu case was confirmed. The New Mexico Activities Association also indefinitely suspended athletic and activity programs at participating schools across the state.

In Arizona, all 10 public schools in the border city of Nogales canceled classes this week after a student tested positive for swine flu.

Officials in several other states also announced plans to close schools where students were either confirmed or suspected to have swine flu.

As of Sunday, there were 245 confirmed cases of the virus in 35 states.