An increasingly rare skin disease, caused by Syphilis's weaker cousin
Pinta, apart from being one of the three ships carrying Christopher Columbus's sailing party to the new world, is a disfiguring skin disease that used to be a significant problem in Central - and South America and is one of the endemic treponematoses. With up to one million cases known in the fifties, these days only a few hundred are being diagnosed annually.
The causative agent is Treponema carateum, a spirochete closely related to the bacterium that causes the scourge of the middle ages, Syphilis. Fortunately, compared to syphilis, pinta is relatively harmless but can cause severe disfigurations. Transmission is directly from human to human, often in cramped and unhygienic circumstances. There is no other vector involved. After the initial infection it takes approximately two to three weeks for the initial lesion to appear: a scaly papule develops on the exposed areas of the extremities. Small satellite lesions will follow (pintids) over the next months. This is accompanied by the painless swelling of lymphnode packets (classically in your groin or armpits). If no treatment is instigated, the third stage of pinta sets in after after a number of years, and the skin becomes thin, whiteish and malformed (an excellent picture of a patient with tertiary pinta can be found here.
Diagnosis is clinical and with the help of a darkfield microscope the spirochaetes can be identified from exsudate out of the lesion.
Treatment is rather easy: One shot of intra muscular penicillin is all that it takes. This is of course the main reason that the disease was so succesfully battled over the last fifty years, but due to unawareness of the symptoms it's staging a comeback.
Sources:
M. Eddleston, Stephen Pierini: Oxford Handbook of tropical medicine. Oxford University Press 1999
http://www.emedicine.com/med/topic1836.htm
http://www.cehs.siu.edu/fix/medmicro/trepo.htm