Syphilis

Syphilis starts with a small, painless sore on the genitals, rectum, or mouth. Weeks later, you might develop a rash that spreads over your body, including the palms and soles, along with flu-like symptoms such as fever and swollen lymph nodes. If untreated, it can progress to severe headaches, difficulty with coordination, memory problems, numbness, and vision issues in the tertiary stage.

Transmission: Syphilis is spread through direct contact with a syphilis sore during vaginal, anal, or oral sex.

Prevention: Prevent syphilis by using condoms, having a mutually monogamous relationship with an uninfected partner, and getting regular STI screenings.