What Is the History of Polio?

There are illustrations dating from Egypt in 1400 BC that show people with withered limbs and a dropped foot, which is particularly characteristic of polio. It's been around for millennia, but it's interesting because it really didn't start to re-emerge or be noted in literature or historical accounts of the day until the 17th century. One of the thoughts as to why polio wasn't an epidemic disease has to do with sanitation. Prior to wide scale water treatment and sanitation measures, children were probably exposed to polio at a very young age,. And then also recovered and had lifetime immunity.