This STI can cause chancres in the Primary Stage, which is the first of the three stages of this infection. The second stage is characterized by a rash and the third stage by cause
severe medical problems.

Syphilis.

Explanation: Syphilis commonly causes chancres in the primary stage of infection. There are stages of syphilis, primary, secondary, latent and tertiary. Prolonged infection of syphilis can cause severe medical problems resulting in damage to the eyes, brain, nervous system and heart.