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Why does the disappearance of a chancre not mean that syphilis is gone?

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Scanning electron micrograph of Treponema pallidum, the spirochete bacterium that is the causative agent of syphilis. — syphilis Scanning electron micrograph of *Treponema pallidum*, the spirochete bacterium that is the causative agent of syphilis.

The disappearance of a chancre does not indicate that syphilis has been cured. While the primary lesion typically heals spontaneously within 10 to 40 days without leaving a scar, the underlying infection remains active in the body.12

If left untreated, the disease progresses to the secondary stage, which may manifest weeks or months later through symptoms such as rashes, fever, and swollen lymph nodes. Following this, the infection can enter a latent period where no outward signs are visible, yet the spirochete Treponema pallidum continues to persist within the body. Without medical intervention—specifically the use of penicillin or other appropriate antibiotics—the disease can eventually advance to the tertiary stage, which may cause severe, irreversible damage to the cardiovascular system, central nervous system, and other organs. Because the infection remains present even after the initial sore vanishes, professional medical diagnosis and treatment are essential to stop the progression of the disease.23