Syphilis is a venereal disease that is easily transferred via bacteria and it affects the entire body. Syphilis proceeds in several stages and may produce a big variety of symptoms. For certain periods of time, syphilis is not noticeable at all and therefore remains undetected.
If not treated, syphilis can have severe, even life-threatening consequences. However, the disease can usually be treated quite easily with antibiotics.
Condoms/femidoms/dental dams during vaginal/anal and oral sex may reduce the infection risk, but do never offer full protection.