For most of human history, we had a lot of bad ideas about how we were getting sick. We also had plenty of bad ideas about how to prevent it, like bloodletting, drilling large holes in the head and drinking arsenic.
We really only started to figure out how to effectively fight infectious disease about 200 years ago, when, inspired by milkmaids, a doctor named Edward Jenner decided to take a closer look at a promising folk remedy - the surprising details we'll leave for the video.
Eventually, he invented vaccination, our first safe and effective way to fight disease. About time!
So what did that do for us? Consider that in 1900, the average person lived only about 30 years. Today, most of us live to 70. We were so successful in such a short time, the U.S. surgeon general reportedly exclaimed in 1967 that we had closed the book on infectious disease.
If only! The conditions that created the rise of human germs are only intensifying. Which means there are more germs emerging now than ever before.
If you missed 'em, catch up on Episodes 1 and 2 below ...