美国有线新闻 CNN 平昌冬奥爆集体感染诺如病毒 1200名安保人员被隔离（在线收听）

First story this Wednesday: sickness has swept over dozens of people working on the 2018 Winter Olympics. But it's not the nasty flu virus you've heard about. What hospitalized 41 security guards in Pyeongchang, South Korea, is norovirus.

Olympics organizers say they suddenly started showing symptoms on Sunday. Officials don't know exactly how the security guards got infected, but the Korean Center for Disease Control and Prevention says they've all been staying at the same building. Organizers are testing the water and food where the security guards are staying and they're checking to make sure their bedrooms are virus free.

All of those who'd caught norovirus are stable. But in order to help contain the disease, a total of 1,200 security guards had to be taken off duty. This would have had a significant impact on security for the games, so South Korea deployed 900 members of its military to help keep the event safe. They'll be doing the security checks at 20 of the venues where events are held.

Though the opening ceremonies are scheduled for Friday, the first events will actually start the day before. So, health officials want to get a handle on this before it has the chance to spread to athletes, trainers, coaches and tourists.

ELIZABETH COHEN, CNN SENIOR MEDICAL CORRESPONDENT: Norovirus is one of the most contagious bugs out there.

SUBTITLE: How viral is norovirus?

COHEN: The amount of norovirus that can fit on the head of a pen can get a thousand people sick. About 20 million people a year get sick from norovirus in the United States. Eight hundred people die, about 60,000 end up in the hospital.

Norovirus is the number one cause of food poisoning outbreaks in the United States. Infected food workers, they're responsible for about 70 percent of the norovirus outbreaks in this country.

When people get norovirus, they get vomiting and diarrhea, sometimes it's pretty vicious. Another reason norovirus is so powerful is it can stay on your countertops for up to two weeks and many common disinfectants and cleaners just don't work against it.

So, you can fight norovirus. First of all, wash your hands thoroughly with soap and water. Sanitizers just isn't going to cut it.

Also, avoid touching foods with your bare hands. Use silverware as much as you can. And if you do feel sick, don't prepare foods for other people.