treponema

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of a group of spirochetes of the genus Treponema, including those that cause syphilis, pinta, and yaws.

Century Dictionary and Cyclopedia

1. n. A genus of parasitic flagellates. The best-known species is T. palhdum, the supposed pathogenic micro-organism of syphilis, formerly called Spirochæte pallida.

Wiktionary

1. n. Any of many anaerobic spirochetes, of the genus Treponema, many of which cause infectious diseases

WordNet 3.0

1. n. spirochete that causes disease in humans (e.g. syphilis and yaws)