Syphilis is a sexually transmitted disease(STD) caused by a bacterium. Syphilis can cause long-term complications and/or death if not adequately treated. CDC estimates that, annually, 55,400 people in the United States get new syphilis infections. There were 46,042 reported new cases of syphilis in 2011, compared to 48,298 estimated new diagnoses of HIV infection and 321,849 cases of gonorrhea in 2011. Of new cases of syphilis, 13,970 cases were of primary and secondary (P&S) syphilis, the earliest and most infectious stages of syphilis. In 2011, 72% of P&S syphilis occurred among men who have sex with men.