There are another six probable cases in New York state, all in New York City.
Health officials believe there are likely many more cases of the flu in people who have not been tested. All of New York's cases have been mild.
Earlier Monday, students streamed into St. Francis Preparatory School, happy to return after an outbreak of swine flu but wary of close contact, and some equipped with hand sanitizer in their backpacks.
Swine flu sickened perhaps as many as 1,000 people associated with the Queens high school, according to the city health department. The school 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 had 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."
Both girls kept up with homework through the school's Web site.
Green signs on the school's doors welcomed the students back and reminded them what schedule to follow.
The city has six probable swine flu cases along with the 73 confirmed, said Thomas Frieden, health commissioner. Of those 79, three have no link to Mexico or St. Francis, said Mayor Michael Bloomberg, who welcomed the students back.
P.S. 177, a nearby public school that closed last week after some students came down with suspected swine flu, will remain closed until Wednesday, Bloomberg said.
Of St. Francis' 2,700 students, 204 were out sick Monday, said Brother Leonard Conway, the school principal.
"Of the 204, the vast majority of calls were from parents who said, 'Just to be on the safe side I'm keeping them out for another day or two,"' Conway said.
Some said they didn't have the flu; a few said they were getting over something flu-like, Conway said. No teachers were out on Monday with swine flu, he said.
Conway said students who returned to school Monday "have a lot of work to do" and were "excited about doing it." The students have Advanced Placement and regents exams coming up. To make up the lost classroom time, final exams will start June 16 - later than the scheduled June 11, 12 and 15 - and the same time the regents exam will take place, Conway said.
"I'm just delighted and thank God that we're getting back to normal," he said.
Even as St. Francis reopened, newly confirmed infections and school closures were reported around New York and in other states.
Health officials in Syracuse said Sunday that the 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.
The Deer Park Union Free School District on Long Island announced Saturday it was closing six of its schools until May 10 because three students probably 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.
Brandon Gratta, 15, a freshman at St. Francis, came to school with a small bottle of hand sanitizer at the urging of his mother, a nurse. In addition, he said he planned to wash his hands more frequently, even if he doesn't use the restroom, and especially before lunch.
Gratta, who was not sick and had no symptoms, said he would also heed his mother's advice not to come in close contact with students who appear sick or have colds.
He wasn't worried about being back because he said the school had flushed the air conditioning system and given the building a complete scrubdown, among other safety precautions.
Speaking through the school's public address system, Bloomberg thanked the students for their patience, adding, "It's always good to be back with your friends and back to studying."
In New Jersey, Health Commissioner Heather Howard says the state has received swine flu test kits from the Centers for Disease Control and Prevention, allowing the state lab to confirm suspected swine flu cases.
Howard says the state should be ready to use the test kits by the end of the week.
Seven people in New Jersey have been determined to have the virus. Tests on an eighth person have been sent to the CDC.
A school in Burlington County is closed for two days because two students showed signs of possibly having swine flu.
A Granby child is the latest probable case of swine flu identified in Connecticut.
The unidentified child's specimen is being sent to the Centers for Disease and Prevention for further testing.
There have been two confirmed cases of swine flu in Connecticut, as well as one inconclusive case and 11 probable cases. None required hospitalization.
Connecticut hospitals and community health centers are reporting a decline in the number of patients seeking testing for the swine flu.
MORE ON THE SWINE FLU
Swine flu is a respiratory infection caused by influenza type A viruses that regularly cause outbreaks of influenza in pigs. People do not normally get swine flu, but human infections can occur. Human cases typically involve people who have had direct contact with pigs, but likely person-to-person transmission has now been reported in California, Texas, Mexico and New York City. Again, the cases in Mexico have had a high fatality rate, but the confirmed cases in the U.S. have been mild and all patients have recovered without treatment.
The symptoms of swine flu in people appear to be similar to the symptoms of regular seasonal flu and include fever, cough, sore throat, body aches, headache, chills and fatigue. Some people have reported diarrhea and vomiting as well. New Yorkers experiencing severe symptoms, such as difficulty breathing, should seek health care and treatment. Otherwise, the health department recommends at-home care.
The most effective way to lower the risk of influenza transmission is for people with symptoms to stay home. All New Yorkers should cover their mouths when they cough. Additional precautions:
Swine influenza cannot be transmitted from eating pork or pork products.
For facts about influenza, and more information about swine flu, please visit the health department and CDC Web sites. Some specific resources:
From New York City Health Department
Facts about flu
http://www.nyc.gov/html/doh/html/cd/cdinflu.shtml
From Centers for Disease Control and Prevention
General information about swine flu
http://www.cdc.gov/swineflu/general_info.htm
Swine Flu Case Definitions
http://www.cdc.gov/swineflu/casedef_swineflu.htm
Swine Flu Infection Control and Patient Care
http://www.cdc.gov/swineflu/guidelines_infection_control.htm
Preventing the Flu
http://www.cdc.gov/flu/protect/habits.htm
