Primary syphilis is the early stage of syphilis infection. It is acquired with direct sexually contact with an infected person. I can also be passed from an infected mother to her baby (read more on congenital syphilis).

Usually a skin lesion, also known as chancre, occurs within 3 weeks of contact.  It can be formed in the skin of genitals or mucous membranes of mouth and anus.

The chancre is painless  and usually is healed within 4-8 weeks even left untreated, thus many people do not seek medical care. Even if the chancre is healed the infection is still present.

Sometimes people are unaware of being infected because the chancre cannot be seen as it can be formed inside the rectum or in the cervix.

Read also:

Primary syphilis pictures.

Congenital syphilis.