Cause of syphilis is a bacterium called Treponema pallidum. The most common transmission channel of the disease is trough contact with a patients chancre. The bacterium enters the body through minor wounds or cuts that are on the skin or the mucous membranes.

Syphilis is contagious in its primary and secondary stage and sometimes at the beginning of the latent phase. It is not generally possible to contract syphilis through toilet seats, daily activities, hot tubs, or sharing eating utensils or clothing. In case of a cure there is always the possibility of recontamination if the cured comes in contact anew with a foreign source of syphilis.

Factors that can favor the transmission of syphilis are:

• Sexual intercourse without protection.
• Multiple sexual partners.
• Sexual intercourse between men.
• HIV infection, which causes Aids.