CHICAGO (CBS) – It’s making kids sick, forcing them to miss school. And it’s spreading. Hundreds of cases of the norovirus have now been reported in Cook County, and in two dozen different areas in the south and northwest suburbs. CBS 2’s Pamela Jones reports.

School kids in suburban Cook County have heard the drill.

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“I wash my hands a lot, stay clean, don’t share drinks or food,” said high school sophomore Jonathan Chaikin.

“I have three kids, I’m very concerned,” said Chaikin’s dad.

Concern over the spread of norovirus is pushing a lot of parents to emergency rooms across the area, with 34 confirmed cases in Illinois so far.

“About two weeks ago, it was like the switch was flipped, and we started seeing a lot of kids. Some adults, but a lot of kids,” said Barbara Weintraub of Northwest Community Hospital. “And sometimes up to half the kids in the pediatric department are here for symptoms consistent with the norovirus.”

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Dr. Meta Carroll works in the pediatric unit of Northwest Community Hospital. She’s just getting over the illness herself.

“I had shaking, chills and nausea,” said Dr. Carroll. “We’ve seen a lot of it in the ER. It starts with vomiting. And it’s a vomiting that just by a parent’s best efforts, it just doesn’t stop.”

She’s drinking lots of Gatorade. And that’s what pharmacists are advising for people searching store shelves for some relief.

“The biggest thing I’m concerned about is dehydration,” said Walgreens Pharmacy Manager Nancy Davis. “I want to make sure that you’re drinking plenty of fluids. I don’t particularly care if it’s juice or water. Lots of fluids.”

Health officials here in Illinois want people to pay attention to this virus because just a little of it on a faucet or doorknob can infect a lot of people. You have to wash your hands well — for about 15 to 20 seconds.

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A good rule is to sing the “Happy Birthday” song to yourself a couple of times while washing.