Polio

Here's a link (PDF, 2.7 megabytes) to a pretty cool webcomic about the history of poliomyelitis. The gimmick is that the story is being told from a polio virus's point of view, as it speaks in an unnamed 12-step encounter group. (Infections Anonymous?)



I never knew that polio was spread in sewage and was pretty much endemic in early populations (in the same way malaria still is in some parts of Africa), and that 96% of cases are totally asymptomatic. Only about 0.16% of people who encountered polio in ancient times ended up with some form of paralysis.



So why was it treated as such a horrible disease? It seems that as world health and hygiene improved, fewer and fewer people came into contact with sewage, which meant they had less exposure to the polio virus and thus fewer chances to develop immunities to it.  In the developed world, polio went from being endemic to being epidemic, and when it struck, it went straight for the spinal cord and shut parts of it down.



An effective sewage system, while working wonders at stopping other diseases like cholera outbreaks, actually led to the "strengthening" of the polio virus.  Cleanliness led to infantile paralysis.



Think about that the next time you reach for the antibacterial hand sanitizer.