Syphilis is an important sexually transmitted infection. There has been an epidemic of syphilis amongst men who have sex with men in the United Kingdom in the last decade. Early infection with syphilis causes a genital ulcer followed, in the absence of treatment, by a generalised illness often accompanied by rash. Studies on syphilis have been limited because it is not possible to grow syphilis outside of the body. New approaches allow the whole genetic sequence of Treponema pallidum to be obtained from a swab.

In this study residual DNA collected as part of routine patient care of patients seen at sexual health clinics in the UK will be used for sequencing. No patient contact is involved in the study which is limited to whole genome sequencing using residual material from samples. By better understanding the genome of the T.pallidum insights will be gained in to the pathogenesis of this important sexually transmitted disease.

Inclusion Criteria:

• Diagnosis of syphilis

Exclusion Criteria:

• No PCR positive clinical sample

Patients presenting to sexual health services in UK with a diagnosis of syphilis.

We will identify residual T.pallidum DNA from routinely collected clinical samples held at participating clinics/hospitals. Data accompanying these samples will be anonymised and will not include patient identifiable information. Accompanying data will include: city of origin, age, gender, HIV status and sexual orientation.