University of South Carolina School of Medicine: Alvin Fox's "Spirochetes and Neisseria"
Read the sections titled "Treponema pallidum" and "Leptospirosis." The Treponema genus causes syphilis, a common sexually transmitted disease. Take advantage of the PowerPoint lecture slides as you study.
Click http://web.archive.org/web/20160407063148/http://microbiologybook.org/fox/spiro-neisseria.htm link to open resource.