After milkmaids helped discover vaccination, we spent the next 150 years learning how to keep ourselves safe from germs. By the 1960s, we thought the battle was finally over. If only!

Ten thousand years ago, many of our deadly human diseases didn't exist. What happened?

Our first germs didn't do much damage, until we gave up our hunter-gatherer ways and started farming. Episode 1 of a three-part animated miniseries on the battle between humans and germs.