Congenital syphilis in Switzerland: gone, forgotten, on the return

Acquired syphilis has re-emerged in many Western European countries. In contrast to international guidelines, screening for syphilis in pregnancy is not generally recommended in Switzerland. There has been an increase in the incidence of laboratory syphilis notifications in recent years, regardless of gender and age.

We conducted a retrospective study, evaluating the total numbers of pregnant women with positive syphilis serology (Treponema pallidum Particle Agglutination assay, TPPA) from 2000 to 2009, and evaluated the clinical management and outcome of their offspring. In addition, we sought to determine cases of infectious syphilis (primary, secondary, and early latent syphilis) reported to the Swiss Federal Office of Public Health in women of childbearing age, which has previously been shown to precede changes in the incidence of congenital syphilis within a population.

Out of 13,833 women who gave birth at our institution, positive syphilis serology was found in 9 pregnant women during the 10 years studied. A total of 6 pregnant women were diagnosed having syphilis infection during pregnancy. Regarding their offspring, 8 of the 9 newborns were tested serologically. One neonate experienced congenital syphilis because the adequately treated mother developed re-infection after treatment. Within the Swiss population, infectious syphilis cases in women of childbearing age increased substantially from 2006 to 2009.

The epidemiologic data suggest that congenital syphilis could become a medical problem in Switzerland due to the rise of infectious syphilis cases in women of childbearing age that have been shown to be followed by changes in the congenital syphilis incidence. The persistence of congenital syphilis in Switzerland along with this rise of infectious syphilis in women of childbearing age suggests a potential for improvement of prenatal care and syphilis control programmes.