Objectives To describe an outbreak of infectious syphilis in rural North Wales and the control measures implemented.

Methods Following reports of an increase of syphilis in North Wales, a multidisciplinary Outbreak Control Team (OCT) was established. A multilevel prevention and control response was initiated, including: active case surveillance, partner notification and treatment, sexual network analysis, awareness raising with professionals and affected communities, point-of-care syphilis testing at a sauna and a health promotion campaign targeting users of men who have sex with men (MSM) social network mobile phone applications (apps).

Results Four cases of infectious syphilis were diagnosed in clinics in North Wales per 100 000 population in 2013 compared with a mean of one case per 100 000 in the preceding decade. Diagnosed cases peaked in January 2014, declining in the first half of 2014. Initial cases were clustered in the westerly rural counties of North Wales and were predominantly white men, self-reporting as MSM (median age: 34 years, range: 17–61). Point-of-care testing at a sauna did not identity further new infections, suggesting that the cluster was relatively focused and had probably been detected early. The use of apps to find sexual partners was a feature of the network affected. A health promotion campaign, initiated by the OCT, targeting men using MSM apps reached 92% of the 755 men messaged.

Conclusions The outbreak was successfully controlled. However, it is difficult to determine which of the interventions implemented were most effective. Future outbreaks should be used as an opportunity to evaluate interventions using apps.