Treponema pallidum is a bacterium with various subspecies that cause the diseases syphilis, bejel, and yaws. It is transmitted only among humans.
Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum subspecies pallidum. The signs and symptoms of syphilis vary depending in which of the four stages it presents. The primary stage classically presents with a single chancre. In secondary syphilis, a diffuse rash occurs, which frequently involves the palms of the hands and soles of the feet. There may also be sores in the mouth or vagina. In latent syphilis, which can last for years, there are few or no symptoms.
Bejel, or endemic syphilis, is a chronic skin and tissue disease caused by infection. Typically, endemic trepanematoses begin with localized lesions on the skin or mucous membranes.
Yaws is a tropical infection of the skin, bones and joints caused by the spirochete bacterium Treponema pallidum pertenue. The disease begins with a round, hard swelling of the skin, 2 to 5 centimeters in diameter. This initial skin lesion typically heals after three to six months. After weeks to years, joints and bones may become painful, fatigue may develop, and new skin lesions may appear.