Syphilis is a sexually transmitted disease (STD) that can be passed on to others through sexual, mother-to-child, and blood transmission. Syphilis is a sexually transmitted disease (STD) caused by infection with the syphilis spirochete, which is contagious and therefore can be passed on to others. If you have sexual contact with a person who has syphilis, you have a higher chance of getting infected if you do not take protective measures. If the mother has syphilis, after the fourth month of pregnancy, the syphilis spirochete will be passed from the pregnant woman to the fetus through the placenta, and the transmission route is mother-to-child transmission. Some people may also get syphilis if they share needles and injections with a person who has syphilis, or if they share razors, which is a bloodborne infection. Syphilis can be passed on to others. If you are tested and found to have syphilis, you should seek medical treatment to avoid delaying your condition.