ALTHOUGH there is debate about its geographic origin, syphilis has been clearly described since the 15th century, as has its sexual mode of transmission.¹ In the early 20th century, syphilis was a leading cause of neurologic and cardiovascular disease and a major public health problem.² Even before the introduction of penicillin, the combination of effective therapy and organized public health measures caused syphilis rates in the United States to decline, and by the mid-1950s the disease was relatively uncommon. Between 1955 and 1985, relatively few cases of syphilis were diagnosed (Fig. 1); as a result, many clinicians are now unfamiliar . . .