It is already impacting the stock market big time - and having an idiot in charge in the US doesn't help. Trump is trying to make it if there is no real big issue and that the US government have things under control, only no one believes him and his words only makes people more scared.
Both examples you mention seem likely. Same thing with the Tour de France and really any international events, not to mention local events as well in the areas especially affect only what areas is that. Think weddings, parties, political meetings, people using public transport...
An example, the mess in Italy. Here in Denmark we now have two Danes that was on holiday in Italy that has gotten ill. One of them registered today, but he arrived home from Italy on the 14th so for two weeks he has been living his normal life here in Denmark. Maybe he hasn't infected others, but maybe he has and they may have infected others... And lots of people from all over has been on skiing holidays in Italy.
As for the low point with stocks, my best guess if to look for the values to stabilize, hope that a new drop won't happen and then make the move only as always it is taking a bet so only do so with money you can afford to lose.