No 35 - 2010

Syphilis 2009
PCR diagnostics used for genital ulcers

Syphilis 2009

In 2009, a total of 326 syphilis cases were notified, including 43 cases of late-stage syphilis which is not notifiable, EPI-NEWS 23/09. In all, 283 cases had been acquired within the past two years and were therefore notifiable; one person was notified twice. A total of 252 cases were detected by serology at the SSI and notified, including 24 cases which were also PCR-positive. Seven cases were notified but detected exclusively by PCR, and 24 cases were detected by serology at the SSI, but not notified by the physician who had ordered the serological test.

No cases of congenital syphilis were notified.

A total of 202 cases occurred among males, 22 among females, and in one case sex and age were not stated, Table 1.

The median age was 37 years for both genders (range: 17-82 years for males, 21-69 years for females).

Notified cases

Among the 259 cases, 247 (95%) were males and 12 females.

Among the males, 215 were Danish-born, 28 were immigrants, three were tourists, and in one case the country of origin was not stated. Among the females, seven were Danish-born, four were immigrants and one was a tourist.

The number of notified cases of newly acquired syphilis has thus been increasing since 2008, Figure 1.

Table 2 shows the distribution by area.


Nine females were infected in Denmark and for three, the country of infection was not stated.

Among the males, 213 (86%) were MSMs (males who have sex with males), among whom 187 (88%) were infected in Denmark, six abroad, and in 20 cases, the country of infection was not stated. Thirty (30%) were heterosexually infected, among whom 18 (60%) were infected in Denmark, four abroad, and in eight cases, the country of infection was not stated. In four cases, the mode of infection was not stated.

Syphilis and HIV

Information on HIV-status was avaliable in 236 cases, among whom 88 (37%) were HIV-positives; all were males, except for one female who had previously been a male.

Among the HIV-positive males, three were notified as having been infected with syphilis by females, the rest by MSMs. Among the MSMs for whom HIV-status was stated, the majority were HIV-negatives as

opposed to the results collected in the four previous years, Figure 2.

A total of 36 MSMs and two heterosexually infected males had previously been notified with syphilis, 32 of whom were HIV-positives. Twenty-five of those who had been notified repeatedly had more than one previous notification, including 21 HIV-infectees. Among the repeatedly notified HIV-positive MSMs, five (20%) had been notified as HIV-negatives in connection with a previous syphilis case.


The increase in the number of syphilis cases among MSMs continues. 2010 has already seen nearly as many notifications as were recorded in all of 2009.

Syphilis is now seen among MSMs who are, or believe they are, HIV-negative. This can be deducted from the number of notified cases, as the number of HIV-positive MSMs notified with syphilis rose by 25% relative to 2008, while the increase among HIV-negative MSMs was 135%.

Syphilis is a marker of unprotected sex, and therefore also a marker of risk of HIV-infection.

HIV-infection from newly infected persons who have yet to be diagnosed with HIV constitutes a risk, as HIV is most infectious during its initial stage. 

Patients who are tested for syphilis, should be tested for HIV simultaneously, EPI-NEWS 46-09.

(G. St-Martin, S. Cowan, Department. of Epidemiology, S. Hoffmann,

J.S. Jensen, Department for Microbiological Surveillance and Research)

PCR diagnostics used for genital ulcers

The SSI has developed a PCR for detection of Treponema pallidum and certain other relevant bacteria in suspected chankers and other genital ulcers. Patients in these early stages often have not developed detectable antibodies and some patients will remain seronegative if treatment is initiated early. The same sample can also be tested for LGV, chancroid and herpes virus. In 2009 a total of 31 syphilis cases were diagnosed using this method, which will become available as a routine test shortly.

(J.S. Jensen, Department for Microbiological Surveillance & Research)

Individually notifiable diseases and selected laboratory diagnosed infections 

(Department of Epidemiology)

1 September 2010