No 22 - 2018
In 2017, Statens Serum Institut (SSI) recorded 545 syphilis cases in 521 persons.
A total of 487 (89%) of the cases occurred in 463 men and 58 (11%) in 58 women, as 24 men had two cases in the course of the year.
In 1994-2001, syphilis was very rare in Denmark; the period saw less than 20 notified cases per year. As from the turn of the millennium, an increase has been observed in the number of cases. This increase was particularly pronounced in the 2006-2011 period. Following a decrease in the number of cases in 2012, the number of syphilis cases followed an increasing trend, but now the number of cases has once again decreased. However, this decrease was mainly seen among MSM.
The typical chancre is symptom-free and also often localised to places where it goes undetected by the patient (vagina, rectum, oral cavity). Interruption of chains of infection therefore cannot be based on symptom-triggered visits to the physician. Therefore, it is essential that MSM are tested frequently, even if they have no symptoms. This leads to the diagnosis and treatment of otherwise unacknowledged syphilis, whereby infection chains can be broken.
Campaigns have been run to motivate more MSM to undergo frequent testing for sexually transmittable infections, including HIV, syphilis and gonorrhoea. These campaigns seem to have been successful with respect to syphilis as the described increase in syphilis - an infection that is more common among MSM - has not continued. We hope that the introduction of PrEP (medication-based HIV prophylaxis) will mean that even more MSM are tested frequently for syphilis, among others, whereby infection chains will be broken more often.
All MSM are recommended annual testing for sexually transmittable infections including HIV, and MSM who lead an active sex life and who do not always use a condom are recommended testing 2-4 times annually. This test frequency is also recommended by the US Centers for Disease Control and Prevention (CDC) and the National Health Service (NHS) in the UK.
The share of the notified syphilis patients (particularly MSM) who has been tested for HIV is very high. This is encouraging, and it is important that MSM who are tested for syphilis also undergo testing for HIV, EPI-NEWS 46/09, chlamydia, lymphogranuloma venereum (LGV) and gonorrhoea, cf. the Danish Health Authority’s guidelines on the Prevention, Diagnosis and Treatment of Sexually Transmittable Infections.
Since 1 January 2010, the general screening of pregnant women has included syphilis, EPI-NEWS 27-33/2010. In case of a positive screening test, confirmatory serological tests need to be made to confirm or refute the screening result. In several cases, it has been necessary to remind the patient’s GP about this, and in some cases syphilis that obviously needed treatment was detected through confirmative tests in these women.
In 2017, a total of 10 cases of syphilis were detected among pregnant women, including 8 Danish women. It is known that nine of the women received treatment and none of these women transmitted syphilis to their new-born child. Furthermore, no cases of syphilis in children were detected in 2017.
PCR is well-suited for detection of Treponema pallidum in chancre material and is typically positive before antibodies can be detected. Even so, serological testing is needed to monitor the treatment effect.
Syphilis is notified to the Department of Infectious Disease Epidemiology and Prevention, SSI, on form 1510, which is available for download here.
(S. Cowan, M. Wessman, Department of Infectious Disease Epidemiology and Prevention, J. Kähler DIAS, S. Hoffmann, Bacteria, Parasites and Fungi)