How syphilis is transmitted between sexual partners is unclear. Asymptomatic detection i.e. detection of syphilis bacteria (Tp) from anatomical sites without lesions, in patients with syphilis infection, suggests that asymptomatic transmission from these sites may play a role. However, no existing studies have established whether the syphilis bacteria (Tp) detected was viable. This means it is not known if the bacteria at this anatomical site is alive and therefore able to transmit the infection. Further, studies have focused mostly on men who have sex with men, resulting in a lack of evidence regarding anal shedding in men-who-have-sex-with-women only and women (regardless of sexual behaviour), and no data on asymptomatic vaginal shedding in women. This study will explore:
1. Patterns of Tp detection in women and men-who-have-sex-with-women only. 2. Whether detected Tp from each asymptomatic anatomical sites is viable 3. Duration of Tp detection and viability (alive and transmissible bacteria). Patients presenting to a participating sexual health service (overseas only) for management of suspected/confirmed early infectious syphilis will be eligible. During the routine clinical examination, participants will have additional oral and anal swabs, urine, vaginal swab (where relevant), penile skin swab (where relevant) and blood sample collected, in addition to the routine samples taken from the same sites and routine serology collected when syphilis is diagnosed.
None
Men, transwomen, or other people, with a penis, who have had any sexual contact, including kissing, oral sex or anal sex, with men (or any other individual with a penis) in the previous one year.
Individuals who have received antibiotic treatment within 1 month prior to enrolment, with the EXCEPTION of metronidazole.
Diagnosis of late latent syphilis (>1 year) or latent syphilis of unknown duration.
Women and Men-Who-Have-Sex-With-Women-Only with early infectious syphilis
Case-only
Cross-sectional
No Intervention: Observational Cohort
Other interventionNo intervention: Observational study
6
Treatment groupsSee each treatment group below.
Number of Biological Samples Testing Positive for Treponema pallidum DNA by PCR
This outcome measures the presence of Treponema pallidum (Tp) DNA in collected biological samples-including lesion swabs, blood, urine, saliva, and oral/anal/genital swabs-using a validated T. pallidum polymerase chain reaction (Tp PCR) assay. Data will be reported as the number and proportion of samples that test positive, stratified by: * sample type, * clinical stage of syphilis, * anatomical site (where applicable), * and participant characteristics relevant to the SOS Global protocol. No scale is used; this is a binary laboratory outcome (PCR positive / PCR negative).
Load of Treponema pallidum DNA in Positive Biological Samples by In-house Quantitative PCR (qPCR) assay
This outcome measures the load (copies/mL) of Treponema pallidum (Tp) DNA in collected biological samples-including lesion swabs, blood, urine, saliva, and oral/anal/genital swabs-using an in-house validated quantitative T. pallidum polymerase chain reaction (Tp qPCR) assay. Data will be reported as a comparison in load between anatomical sites and by clinical stage of syphilis.
Number of Treponema pallidum-Positive Samples Demonstrating Viable Organisms via Novel In-house Viability Assay
This outcome measures the viability of detected Treponema pallidum in PCR-positive biological samples. Viability is assessed using a novel in-house viability assay. Results will be summarised as the number and proportion of Tp PCR-positive samples that contain viable organisms, stratified by sample type and clinical/epidemiological variables specified in the SOS Global protocol. This outcome focuses on confirming whether Tp organisms in collected specimens are capable of establishing infection, rather than merely detecting genetic material. The viability assessment does not result in a continuous scale; it is a binary laboratory outcome (viable / non-viable).
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