SYPHILIS

a sexually transmitted infectious disease caused by the spirochete bacterium Treponema pallidum. Stages of syphilis are primary (a nonpainful chancre in the mouth or anogenital area), secondary (a generalized rash, including the palms and soles, which occurs several weeks to a year later), a dormant stage in which the spirochetes remain in the body without causing symptoms, and tertiary (which may affect many organs including the brain, leading to dementia [neurosyphilis] and death). In immunocompromised persons, syphilis may be progress more rapidly and be resistant to treatment. Penicillin is the usual treatment.