James Meek, Claire McCausland and Debbie Brittain
Lecturers, University of Central Lancashire
Syphilis is a bacterial, sexually transmitted infection caused by the spirochaete Treponema pallidum (Figure 1). It can be transmitted through unprotected oral, anal and vaginal sexual intercourse as well as by vertical transmission during pregnancy or via a blood transfusion. The incidence of syphilis fell significantly after the Second World War with the introduction of penicillin; however, diagnoses have increased since 1997 within the developed world . Public Health England (PHE) data from 2013  reports 3,249 diagnoses of syphilis, with the vast majority of cases seen in men who have sex with men (MSM); the number of infections has continued to gradually increase over the last 5 years (see Table 1). Most MSM diagnosed with syphilis are aged between 25 and 44 years and 40% of MSM are HIV positive at the time of their syphilis diagnosis . Syphilis is endemic in Manchester, Brighton and London; however, pockets of infection have been seen across the whole of the UK. An outbreak is being investigated in semi-rural north-west Wales amongst 49 males, of whom 37 identified themselves as MSM; four of this latter group are also co-infected with HIV. One-third of the men diagnosed admitted using mobile-positioning dating technology, suggesting that they had met sexual partners locally. Further outbreaks have been seen in the East of England, Yorkshire and Humberside, and Lanarkshire and Tayside in Scotland . Read more. . .