SYPHILIS

systemic disease that is caused by the spirochete bacterium Treponema pallidum. Syphilis is usually transmitted through sexual contact, but it occasionally occurs congenitally from infection in the mother. Another form, endemic syphilis, is nonvenereal (not related to sexual contact) in spread and is localized in parts of the world where climatic, economic, and social conditions favour its development. The causative organism of venereal syphilis is a corkscrew-shaped bacterium with regular, tightly wound coils. This bacterium, T. pallidum, averages 8 to 10 microns in length. The bacterium requires moisture to exist, so continuous moisture is a necessity for the transfer of the microorganism from one person to another. The most common means of such transmission is sexual intercourse. T. pallidum's dependence on moisture is the sole reason that syphilis is classed as a sexually transmitted disease. In the body's tissues, the spirochete bacteria reproduce and remain present for the lifetime of the infected person unless destroyed by treatment. Syphilis is effectively treated with penicillin, which kills the spirochetes. The historical origin of venereal syphilis is obscure. Indisputable reference to it in European literature occurred only after the return of Columbus from the New World, and a widely held theory of a New World origin was supported when evidence of treponematosis was found in the skeletal remains of pre-Columbian American Indians. On the other hand, leprosy in Europe before 1500 was considered highly contagious, was associated with sexual contact, had hereditary features, and was said to respond to mercury therapy; therefore, it is likely that many cases thought to be leprosy were actually syphilis. After the post-Columbian outbreak, much was learned about syphilis. Treatment with mercury was widespread, and in 1836 potassium iodide was introduced; but the first successful drugSalvarsan (606)was developed in 1909 by the German bacteriologist Paul Ehrlich. Much was learned about the course of the disease from the infamous Tuskegee syphilis study (193272). The use of antibiotics developed in 1943 after the discovery by the American physician John Friend Mahoney and others that penicillin was an effective treatment for nonadvanced cases of syphilis.