(AP) -- City officials announced a rising toll of the largest cluster of swine flu cases in the nation Monday as anxious New Yorkers rushed to drug stores to buy face masks in response to a global health scare.
Mayor Michael Bloomberg stressed that the disease hadn't left a Queens school and that patients were quickly recovering, distancing it from a swine flu outbreak in Mexico that has killed more than 100 people.
"This remains an isolated incident," Mayor Michael Bloomberg said, advising New Yorkers not to buy surgical masks and saying the city was safe for tourists. "There is no reason for anyone outside of the St. Francis community to stay home."
The number of confirmed cases in New York rose from eight to 28 on Monday. The city said it has an additional 17 probable cases. All of the cases involved students, their relatives and at least one teacher from the St. Francis Preparatory School in Queens, city officials said.
More than 160 sick students were treated at the school nurse's office Thursday and Friday, and Health Commissioner Thomas Frieden said he expected more cases from the community to be confirmed. Some students received doses of Tamiflu, the medication that can help alleviate symptoms of the flu.
The rising number of cases put the city on edge. People were showing up at hospitals asking to be tested for swine flu when they had light flu symptoms. New Yorkers had depleted some pharmacies' stockpile of paper face masks by Monday morning.
"We sold several boxes today," said Gary Halpern, the pharmacist at Caligor Pharmacy in Manhattan. "At least triple what we normally sell."
St. Francis students began lining up at the nurse's office on Thursday, with aches, pains and fever. Abigail Medina-Masilang said she sat down determined to make it through an English test Thursday, when she got "really hot inside" and asked to be excused. The 17-year-old senior said a small crowd was outside the nurse's office, including one who threw up outside the door.
Health officials defended their response to the outbreak. Health Department crews didn't show up to test sick students until 3:30 on Friday, when almost everyone had gone home. That limited the number of students the department could test.
"By the time we knew there was a problem at St. Francis, anybody at the school who was going to be affected, we think already was," Bloomberg said Monday.
Frieden said nearly all the St. Francis patients were improving and none were getting worse. He and Bloomberg said the New York cases do not appear anywhere near as serious as the deadly outbreak in Mexico, where churches and discos have closed to the public and most residents walk the streets with paper masks. The strains between New York and Mexico match, but the symptoms are far more mild here.
The number of confirmed swine flu cases in the United States stands at 42. The outbreak also has sickened people in New York, Kansas, California and Texas. Health officials in Michigan said they have one suspected case and five are suspected in New Jersey.
Many of them had recently visited Mexico, including several students at St. Francis who had recently come back from a spring break trip to Cancun.
They didn't include teachers, although 10 teachers at the school now have flulike symptoms, said Brother Leonard Conway, head of the school. Parents are calling saying more students may be infected, he said.
"We are very concerned about our students," he said.
A 20-student school in Rye, 21 miles north of New York City, was closed and scrubbed down as a precaution Monday because several students and teachers had flu-like symptoms over the last week, superintendent Edward Shine said.
No swine flu cases were reported, but "in light of news reports, we are going to be very cautious," he said.
Associated Press writers Jim Fitzgerald, Samantha Gross and Amy Westfeldt contributed to this report.
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