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What is syphilis?
Syphilis is a Sexually Transmitted Infection (STI) caused by a bacterium (germ).

How can a person get syphilis?
Syphilis is spread from person to person through direct skin to skin contact with a syphilis sore. Syphilis sores may be present on the vagina, penis, anus, mouth, lips or in the rectum. An infection occurs during vaginal, anal, or oral sex. Syphilis can be passed even if the syphilis sore is not seen or felt, so people can pass syphilis even if they don’t know they are infected. Syphilis can also be passed from a pregnant mother to the baby during birth.

Who can get syphilis?
Anyone who is sexually active can get Syphilis. Having unprotected sex (sex without a condom) increases the chance of getting syphilis. While men and women are at risk for the infection, more than half of the reported cases in the U.S. are in men who have sex with men (MSM).


Many people do not have symptoms. If symptoms do occur, they may start 10 to 90 days after infection, but the average is 21 days. Some people may not develop symptoms for years.

For those who do have symptoms, the most common ones are:

  • Sores or bumps on your mouth, anus, vagina, penis, or testicles (balls) 
  • A rash on your whole body, including your hands and feet   
  • A fever 
  • Swollen glands 
  • These symptoms will go away but the individual will remain infected. The infection will last through someone's lifetime if it is not treated.

How long can an infected person spread syphilis?
A person with a sore or bump can spread the syphilis from the time they are infected until they are treated. Because these sores may not be visible, people can pass the infection to others without knowing it. Once treated, you can pass the germ until the sores are completely healed. The longer an infected person is left untreated, the higher the risk of serious long term problems.


How can I find out if I have syphilis?
The only way to know for sure if you have syphilis is to get tested. A healthcare provider usually tests for syphilis from a blood sample. Because untreated syphilis can cause problems for a fetus (unborn baby), all pregnant women should be tested for syphilis. People whose sexual activities place them at risk for syphilis should be tested regularly so they can be treated quickly if infected.

To find a place to get tested near you, click here or call the Mayor’s Health Line (MHL) at 617-534-5050 and Toll-Free: 1-800-847-0710


Can syphilis be treated?
Yes, syphilis is usually treated with antibiotic pills or shots.

Should my partner get treated?
Yes. You can still get syphilis again even after being treated so it is important to have all recent or regular sex partners treated at the same time so you don’t get infected again.

Related health problems:
If left untreated, syphilis can cause serious health problems. Long term infection without treatment can damage internal organs. In addition, persons with syphilis are up to 5 times more likely to acquire HIV if exposed.

Can syphilis affect a pregnant woman and her fetus?
Yes. Syphilis can cause serious problems in a pregnant woman and her fetus.

​For more information, please see our fact sheet here.

Boston Public Health Commission
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