You talk about the causes and the effects. So what happens when a bunch of dirty little fleas knock off half of Europe's population in less than a decade from 80 million down to about 30 million people? Well, number one, you're going to have a healthier population. Not only is natural selection kicked in, and I feel bad for saying it, but it's true. You have people now that are passing along genes with a very stronger immune system that are going to be able to survive for longer. The life expectancy is going to go up, not to mention that you have a better diet now. You have a surplus of food because you have less people that are eating.