There’s a reason why people panic when they hear norovirus. It is extremely contagious and difficult to control. I’ve had it and the plethora of pain that accompanies it is not pleasant.

IOL reports:

Norovirus cases at the Pyeongchang Winter Olympics have risen to nearly 200, organisers said on Monday, despite an intense battle to contain the outbreak.
Seventeen new cases have taken the total to 194, although 147 of those affected have already been released from quarantine, they said.
About 1,200 security guards were quarantined and replaced by hundreds of soldiers when the highly contagious bug first came to light last week.
Officials say they are doing everything they can to stop more people getting the virus, which causes diarrhoea and vomiting and can be spread by contaminated food and water.
Any illness spreading to the competitors would be a major embarrassment to hosts South Korea.