Neurosyphilis in the mixed urban-rural community of the Netherlands

Neurosyphilis is caused by dissemination into the central nervous system of Treponema pallidum. Although the incidence of syphilis in the Netherlands has declined since the mid-1980s, syphilis has re-emerged, mainly in the urban centres. It is not known whether this also holds true for neurosyphilis.

The epidemiology of neurosyphilis in Dutch general hospitals in the period 1999-2010 was studied in a retrospective cohort study. Data from the Dutch sexually transmitted infection (STI) clinics were used to analyse the number of patients diagnosed with syphilis in this period.

An incidence of neurosyphilis of 0.47 per 100 000 adults was calculated, corresponding with about 60 new cases per year. This incidence was higher in the western (urbanised) part of the Netherlands, as compared with the more rural areas (0.6 and 0.4, respectively). The number of patients diagnosed with syphilis in STI clinics increased from 150 to 700 cases in 2004 and decreased to 500 new cases in 2010. The sex ratio was in favour of men, yielding a percentage of 90% of the syphilis cases and of 75% of the neurosyphilitic cases. The incidence of neurosyphilis was highest in men aged 35-65 years, and in women aged 75 years and above. The most frequently reported clinical manifestation of neurosyphilis was tabes dorsalis. In this study, 15% of the patients were HIV seropositive.

The incidence of neurosyphilis in a mixed urban-rural community such as the Netherlands is comparable to that in other European countries. Most patients are young, urban and men, and given the frequent atypical manifestations of the disease reintroduction of screening for neurosyphilis has to be considered.