From The Collaborative International Dictionary of English v.0.48:
Yaws \Yaws\, n. [African yaw a raspberry.] (Med.)
A disease, occurring in the Antilles and in Africa,
characterized by yellowish or reddish tumors, of a contagious
character, which, in shape and appearance, often resemble
currants, strawberries, or raspberries. There are several
varieties of this disease, variously known as framboesia,
pian, verrugas, and crab-yaws.
[1913 Webster]