(LAS VEGAS) -- Dozens of children and adults who are in Las Vegas for the National Youth Football Championships have been hospitalized after coming down with a mystery illness.
The mystery disease shows flu-like symptoms, including vomiting. ABC News Chief Health and Medical Editor Dr. Richard Besser says "norovirus" may be the cause.
"Norovirus is the largest cause of outbreaks of gastroenteritis stomach flu in the United States-- 20 million cases a year," Dr. Besser said. "This is the peak season."
"It's one of the nastiest germs around, 'cause it spreads from person to person through contact. It spreads through food, and also spreads from contaminated surfaces, so it's one of the most contagious ones we see," Besser said.
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