Primary syphilis

Syphilis is a sexually transmitted disease caused by the bacterium Treponema pallidum. Primary syphilis presents as a small painless open sore 3 to 6 weeks after exposure. Although the lesion heals within 6 to 8 weeks, the untreated organism will continue to multiply unchecked, causing many complications. Infection may last for 30 years or more and result in severe neurological complications.