Caption

Scanning Electron Micrograph of Treponema pallidum on cultures of cotton-tail rabbit epithelium cells. The cause of syphilis, this microscopic bacterial organism is called a spirochete, a worm-like spiral-shaped organism that wiggles vigorously when viewed under a microscope. Treponema pallidum was discovered in 1905 by the German bacteriologist Fritz Schaudinn (1871-1906) who named it, putting together the Greek trepo (I turn) and nema (thread) with the Latin pallida (pale) to make a pale turning thread. In the United States, over 35,600 cases of syphilis were reported by health officials in 1999.