Editing Yaws (section)

==Cause==
Yaws is caused by infection with bacteria of the ''[[Treponema pallidum]]'' subspecies ''pertenue''.<ref name=WHO/> The initial yaws wound contains infectious bacteria, which are passed onto others through skin-to-skin contact, typically during play or other normal childhood interactions.<ref name=WHO/>{{sfn|Hotez|2022|p=218}} Early (primary and secondary) yaws lesions have a higher bacterial load, thus are more infectious.<ref name=yaws/> Both papillomas and ulcers are infectious.<ref name=WHO/> Infectivity is thought to last 12–18 months after infection, longer if a relapse occurs. Early yaws lesions are often itchy, and more lesions may [[Koebner phenomenon|form along lines that are scratched]]. Yaws may be evolving into less conspicuous lesions.<ref name=yaws/> After a new person is infected, an infectious papilloma will form within 9–90 days (on average 21 days).<ref name=WHO/>

''T. pallidum pertenue'' has been identified in nonhuman [[primates]] ([[baboons]], [[chimpanzee]]s, and [[gorilla]]s) and experimental [[inoculation]] of human beings with a [[simian]] isolate causes yaws-like disease. However, no evidence exists of cross-transmission between human beings and primates, but more research is needed to discount the possibility of a yaws animal reservoir in nonhuman primates.<ref name=Mit2013/>