As the 2018 Winter Olympics begin in South Korea, the country’s Centers for Disease Control and Prevention has confirmed 128 cases of norovirus--up from just 32 cases a few days ago.

At least 1,200 of those affected with even one symptom of the illness--which happen to be Olympic security personnel temporarily residing at a Pyeongchang youth training center--have been quarantined. In their place are 900 military officers to help keep the events safe.

South Korean health officials have said that no Olympic athletes have been affected, however, there is concern as some of the affected security officers did work in areas where athletes are residing.

According to LeeAnn Jaykus, a recent guest on our Food Safety Matters Podcast, “Hand washing is hugely important. In fact, it’s the single most important thing for people attending Olympics,” Jaykus told the press.

It is unclear how norovirus initially sickened workers at the Olympic games. A survey of the water being used for drinking and cooking tested negative for any trace of norovirus bacteria. Additional inspecting of restaurants and other food facilities at the Olympics site is underway.

Here are some quick facts about norovirus, according to the U.S. Centers for Disease Control and Prevention:

• Norovirus, a germ that spreads quickly and easily, causes vomiting and diarrhea that come on suddenly.
• It is found in the vomit and feces of infected people.
• Millions of people get ill with norovirus each year.
• Norovirus can be spread in many ways: direct physical contact with an infected person (handshaking); eating or drinking contaminated food products; touching surfaces or objects with norovirus on them

Frequent handwashing is the best protection against contracting norovirus.

More on norovirus:
Food Safety Matters Podcast Interviews LeeAnn Jaykus, "The Norovirus Woman"