The family Spirochaetales is distinguished by the helical shape of the bacteria. They are too thin to be visualized using routine microscopy but can be viewed using darkfield microscopy. There are 3 genera: Treponema, Leptospira, and Borrelia. The spirochetal disease syphilis is discussed on discussed in Sexually Transmitted Diseases (STDs): Syphilis.

Last full review/revision August 2009 by Burke A. Cunha, MD