What is syphilis?

Dr Rosemary Leonard Syphilis is an infectious disease caused by a germ (bacterium) called Treponema pallidum. Syphilis is one of the less common sexually transmitted infections (STIs) in the UK. The number of cases are, however, rising. In the UK, the rates of infection are highest amongst men who have sex with men. [https://patient.info/health/sexually-transmitted-infections-leaflet/syphilis](https://patient.info/health/sexually-transmitted-infections-leaflet/syphilis)