The new virus that has risen out of China is just an example of how vulnerable we are. People travel the globe and it is so easy for someone who is infected to travel before they know they are sick.
It is very likely that some time in the future we will suffer a pandemic. There have been pandemics in the past…affecting the known world. They did a good job of culling the population.
With the earth being past it’s ability to manage the number of people I do wonder if this would be its way of fighting back. Maybe we have messed too much with Mother Nature.