by Jerome Carter

Created on: January 20, 2011

Syphilis is an infectious disease caused by a strain of the bacteria treponema pallidum.  Other strains of treponema pallidum are responsible for yaws and pinta, two tropical skin diseases that are closely related to syphilis.

Yaws and pinta are mainly spread through non-sexual contact.  Syphilis, on the other hand, is best known as a sexually transmitted disease.  Like yaws and pinta, however, syphilis can also spread through non-sexual contact.

The bacteria that causes syphilis, treponema pallidum, is part of a large class of bacteria known as spirochetes.  The name “spirochete” is a reference to these bacteria’s shape.  Under a microscope, treponema pallidum and other spirochete bacteria look like corkscrew-shaped worms.  There are many different types of spirochete bacteria in nature, most of which are harmless.  Some species of spirochete live on and inside people’s bodies, including in the mouth and gut.  These bacteria are generally harmless, although some species that live in the mouth may contribute to gum disease.

Three types of spirochete bacteria cause disease in humans.  Borrelia and leptospira bacteria are transmitted to humans by other organisms, including rats, ticks and lice.  The infections caused by borrelia and leptospira spirochete bacteria, however, are not well adapted to human hosts and cannot be transmitted from person to person.

Treponema are the third type of spirochete bacteria that cause disease in humans.  Unlike the other two dangerous spirochetes, treponemes are specifically adapted to human hosts.  These bacteria can spread directly from person to person.

The origins of syphilis are unclear.  Some have suggested that the disease evolved from either yaws or pinta, which are caused by different strains of the same bacteria that causes syphilis (cite).  Ethne Barnes suggests that syphilis originated among West African primates, because treponeme infections closely related to the human ones have been found among apes and monkeys there.  Barnes goes on to suggest that the earliest prehistoric human migrants from tropical Africa brought the disease with them as they colonized various parts of the globe.  Another commonly held theory is that syphilis originated in the Americas, and was brought back to the Old World by Christopher Columbus.

Since the mid-nineteenth century many Westerners have viewed syphilis as a sexually transmitted or

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