Syphilis is a bacterial infection caused by direct contact with syphilitic sores during vaginal, anal, and oral sex. Sores can appear anywhere on the body but are usually painless.
You may feel painless sores lasting 3 to 6 weeks, usually on your vulva or penis. During the secondary stage people can develop skin rashes on the body, including their hands and feet, sores in the vagina, or anus; sore throat, weight loss, and headache and muscle pains. During the third stage people can develop damage to the nervous system, heart, and brain.
Antibiotics. You and your partner(s) must be treated to prevent re-infection.
It can lead to skin, bone, heart, brain disease, and blindness.
Know if your partner is infected before having sex. Abstinence is the only way to prevent it 100%. Latex, polyurethane, or polyisoprene condoms can protect you only if they cover the sore, but sores can appear anywhere in the body not covered by a condom.