This article explores how the Syphilis evolved from different forms to become more evolutionary stable.

Syphilis was known to cause “Boils that stood out like Acorns, from whence issued such filthy stinking Matter, that whosoever came within the Scent, believed himself infected. The Colour of these was of a dark Green and the very Aspect as shocking as the pain itself, which yet was as if the Sick had laid upon a fire.”

Those with the acute form of Syphilis will not attract sexual partners, which will prevent the spread of the Syphilis bacterium. This behavior can be seen as evolutionary unstable as the bacterium will remain with host and never spread to healthy individuals. Therefore, Syphilis evolved to be less acute, which resulted in people having more sex. This became evolutionary stable as the bacterium was allowed to spread and reproduce.

What I found interesting was that, Syphilis was originally a skin ailment from South America. However, when it spread to Europe the disease evolved to be sexually transmitted, because physical contact was taboo. It is very interesting how Syphilis changed from the its original form into the form now, and then again into a more docile. The length of Syphilis’ survival shows why Syphilis evolutionary choices are stable.

http://www.nytimes.com/2008/04/29/health/29essa.html?_r=1&ref=science&oref=login