Syphilis is transmitted through direct contact with a syphilis sore. Sores can be hard to detect, they are supposedly not all that painful, and heal up in about a week. Sores can be in people's mouths, so therefore, it would be possible to get syphilis from kissing or any other kind of direct contact. You supposedly cannot get it from toilet seats, etc. There are a lot of good STD websites you could search for more info. The good thing is, it is typically pretty curable.