Syphilis is best described as

• A. A viral infection that resolves spontaneously
• B. A bacterial, chronic sexually transmitted disease that begins with a localized ulcer
• C. A fungal infection of the genitals
• D. An autoimmune disease affecting the nervous system

Answer: (B)

Syphilis is an infection caused by the bacterium Treponema pallidum and is transmitted sexually. It behaves as a chronic sexually transmitted disease that classically starts with a localized, usually painless ulcer called a chancre at the site of inoculation. If not treated, it can spread systemically and progress through several stages over months to years. This description—bacterial, chronic, and beginning with a localized ulcer—fits best, distinguishing it from viral infections, fungal infections, or autoimmune processes.