Study on syphilis aimed to determine the frequency of T. pallidum shedding from potentially asymptomatic sites and the stage of infection at which shedding is most frequent in men who have sex with men.
We did a prospective, cross-sectional study of 200 MSM. All participants had laboratory confirmed primary, secondary, or early latent syphilis.
We swabbed primary and secondary syphilis lesions. Non-lesion samples were collected via oral rinse, oral cavity swab, anal canal swab, urine, and semen. Samples were tested for T. pallidum.
Our study showed that unrecognised oral and anal shedding of T. pallidum occurs in MSM with early syphilis. Most frequent shedding occurred in those with secondary syphilis. This suggests that secondary syphilis is the most infectious stage. This also suggests that earlier detection and treatment of syphilis to prevent progression to the secondary stage might improve syphilis control. Future research is needed to find out the contribution of shedding of T. pallidum from non-lesion sites to transmission of syphilis.
Publications
Treponema pallidum detection in lesion and non-lesion sites in men who have sex with men with early syphilis: a prospective, cross-sectional study
Janet M Towns, David E Leslie*, Ian Denham, Rebecca Wigan, Francesca Azzato, Deborah A Williamson, Darren Lee, Eric P F Chow, Christopher K Fairley, Stephen R Graves, Lei Zhang, Marcus Y Chen
(2021), The Lancet Infectious Diseases,