That famous vomiting bug, Norovirus, has made a visit to the Winter Olympics. Over 100 cases of Norovirus have been confirmed in Pyeongchang.
It appears that the virus started with Olympic security guards before the athletes even arrived.
Two Swiss skiers were then confirmed to have the virus, and were quarantined away from their team.
Norovirus is the most common cause of infectious vomiting and diarrhea. Most people recover within a few days. It can spread very quickly, usually by contact with an infected person. The virus spreads because it is in the vomit and diarrhea of the affected person.
The only way to prevent it is frequent hand-washing, and cleaning contaminated surfaces. However even with these efforts, Norovirus can still be spread for weeks, especially among individuals in close quarters.