In this study the investigators will collect swabs from ulcers or rashes and a blood sample from patients with syphilis and measure both the response of the patient immune system and the genetic sequence of the bacteria. Patients will be enrolled at sexual health clinics in the United Kingdom. Patients will receive standard medical care including standard treatment for syphilis in line with national guidelines. Standard management already includes collection of a swab and a blood sample. For this study an additional swab sample and an additional 5ml of blood will be collected for use in this research project. By better understanding host immune system responds to infection with syphilis the studies aims to gain better insights in to the pathogenesis of this important sexually transmitted disease.