A non-venereal spirochaetal infection caused by Treponema pertenue; it was formerly widespread in most tropical and subtropical regions. It is directly contagious from person to person but infection is also transmitted by flies, clothing, and living in unclean huts. Clinically, the primary stage is characterized by a granulomatous lesion, or papule (framboesioma or ‘mother yaw’) at the site of infection – usually the lower leg or foot; this enlarges, crusts, and heals spontaneously. It appears some 2–8 weeks after infection, during which time fever, malaise, pains, and pruritus may be present. In the secondary stage, a granulomatous, papular, macular or squamous rash occurs; PERIOSTITIS may also be present. The late, or tertiary stage (which appears 5–10 years later), is characterized by skin plaques, nodules, ulcers, hyperkeratosis (thickening of the skin of the hands and feet) and lesions affecting bones. Diagnosis is by demonstration of T. pertenue in exudate from a suspected lesion. Treatment is with PENICILLIN.