Yaws, a tropical infection of the skin, bones and joints is usually caused by the bacterium spirochete. Yaws is easily and quickly transmitted by skin contact with infected individuals. The Bacteria enters through an existing cut or similar damage to the skin. Usually less than a month but within ninety days of infection with Yaws a painless but vivid "Parent Yaw", an ulcerous papule appears on the surface of the skin at the point of entry. This Ulcer is described to have the color of a rasberry and is about 15-45mm in diameter. This initial Ulcer can last for up to nine months and other ulcers will appear on skin as the previous one heals.

If left untreated a secondary stage of Yaws will occur after up to four months. This second stage is marked by more ulcers similar to the first one in appearance, although much smaller. These growths can combine together into a thick fissured plaque. These fissured plaques can occur on the feet and induce a distinctive gait. Secondary growths of Yaws are irreversible.

In approximately 10-20% cases of yaws the disease can progress for over a decade or more to a tertiary stage. This tertiary stage will have destructive lesions to the skin and to the bones. The largest group afflicted by yaws are children aged 5 to 11 years in Latin America, the Caribbean Islands, India, West Africa, Oceania and Southeast Asia. Numbers of Yaws outbreaksTropical Yaws Ryan Fyfe have been increasing over the past years since, the World Health Organization (WHO) funded campaigns against yaws in 1954 to 1963.

Yaws is easily identified from blood tests or by a microscopic examination of a lesion. Treatment for Yaws is by a single dose of penicillin, erythromycin or tetracycline. It is very oncommon for a victim to have recurrence or a relapse.