Treponemes are members of the family Spirochaetaceae, which also contains Borrelia and Leptospira. Although most treponemes do not cause disease in human beings, a few cause substantial morbidity. This chapter briefly reviews the clinical manifestations and treatment of syphilis in adults and the nonvenereal treponematoses, yaws, pinta, and bejel.

SYPHILIS

Clinical Manifestations

Like other treponemal diseases, the clinical manifestations of syphilis are divided into early and late stages. Early syphilis is further divided into primary, secondary, and early latent stages. During the latent syphilis stage, patients have positive serologic tests for syphilis but no other signs of disease. The Centers for Disease Control and Prevention (CDC) classifies patients in the latent stage as having early syphilis if they acquired infection during the preceding year. Otherwise, persons with latent disease are classified as having either late latent syphilis or latent syphilis of unknown duration. Although clinical staging is useful for diagnosis and treatment, it is also imprecise; overlap between stages is relatively common.

PRIMARY AND SECONDARY SYPHILIS

Treponema pallidum, the causative agent of syphilis, usually enters the body through breaks in the epithelium that occur during sexual contact. Some organisms persist at the site of entry, whereas others disseminate via the lymphatic system throughout the body, proliferating and stimulating an immune response. The incubation period of primary syphilis is usually about 21 days, although extremes of 10 to 90 days have been noted.