BABYLON, Suffolk County (WABC) -- There's a mystery illness going around at Babylon High School on Long Island.
Absences at this school, with roughly 700 students, hit 253 by Monday, but by Thursday, those absences were down to 112.
The Suffolk County Health Commissioner Dr. Gregson Pigott says there's no indication of food poisoning from the school cafeteria, so the likely cause is norovirus.
"Norovirus has been circulating throughout the US for the last few months as it does every year, though an increase in cases compared to our COVID-19 pandemic years was reported by the CDC in February," said Dr. Pigott. "We advise people to continue to wash their hands with soap and water for at least 20 seconds and disinfect surfaces to avoid coming into contact with pathogens that cause norovirus."
Some parents are frustrated that the school didn't act sooner.
"Well, my grandsons, both of them, they got really sick ... violently throwing up and diarrhea and everything," said June Trusillo, a grandparent for two of the sickened students.
Norovirus is the leading cause of vomiting, diarrhea, and foodborne illness in the United States.
It spreads through direct contact with a person with norovirus, most often by caring for them, sharing food, or eating food handled by them.
People can also get norovirus by touching surfaces touched by someone who has norovirus.
People are most contagious when they are sick with norovirus illness and for a few days after they feel better.
Symptoms of norovirus illness begin suddenly, typically around 12 to 48 hours after a person is exposed to the virus and resolve within two to three days.
The most common symptoms are vomiting, diarrhea, nausea, and stomach pain. Other symptoms include fever, headache, and body aches. There is no treatment for norovirus.
Experts tell Eyewitness News that they have seen an uptick in area hospitals as well since February, and while norovirus usually passes in about two days, parents should be mindful of the signs of extreme cases.
"If a child is not urinating at least three times a day and you notice that the urine is dark colored, any signs that they're having a fast heart rate when they don't even have a fever, are all signs that they could be quite dehydrated. Quite ill," said Dr. Mundeep Kainth of Cohen Children's Medical Center.
The health department's caseworkers are investigating the outbreak.
"We have spoken to the families of many of the children who were infected and we are pleased that the outbreak was largely contained to the high school, with only a few cases in students in other schools in the district," said Dr. Shaheda Iftikhar, Chief Deputy Health Commissioner and Director of the department's Division of Public Health.
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