Civilization did not develop anywhere yaws or syphilis were endemic. Think about it.

Deirdre: Depends on your definition of civilization. Syphilis came from the "New World" and I would say there were some pretty advanced civilizations there.

Me: Wherein I discover that I did not make sufficient note of the map of archaeologically attested yaws and syphilis in said New World on which I based my conclusion. DAMN! Thanks for pointing that out. Anyway the short story is that a) syphilis was endemic to North America, and not even all of it, while yaws was endemic further south; 2) in South America, civilization developed in cool, dry Andean climates, which do not favour yaws; and 3) the origin of the Maya civilization and the incidence of yaws in Mayans are not known.

(Later.) I'm pretty sure the author was Bruce M. Rothschild. I just can't find the right paper again.

(Later.) So I still can't find the original source but I did find where Rothschild & Rothschild show that syphilis evolved from yaws ca. 2000 ybp on the Colorado Plateau and then spread out, reaching as far as Ecuador by about 800 ybp, when Ecuadorean cultures were already ancient. Syphilis can thrive in any climate but yaws needs a hot, humid climate which does not occur in most of Ecuador. I stand by my original statement.