In December of 2019 a new and very contagious virus was reported in Wuhan, China. This virus caused most people to have respiratory symptoms which were inconvenient and slowed them down for a few days. They recovered without any medical treatment. For some people, though, the virus caused them to get very sick. Their simple respiratory symptoms became very serious, they had a hard time breathing and they needed very aggressive medical treatment. Sometimes it caused people to die.
So many people were getting sick that organizations who watch for illness trends all over the world started to get worried and watched Wuhan very carefully. This was when we began to talk about how to avoid getting this new illness. To understand the things we are being asked to do now we need to understand some things about diseases, how diseases spread and what works to stop disease spread.