Last summer in our newsletter Aids Treatment Update we reported the re-emergence of syphilis in London, following earlier outbreaks previously reported in Brighton and Manchester.
At that time, Tom Paine of the Public Health Laboratory Service (PHLS) told us that the PHLS were “carrying out enhanced surveillance to assess the extent of the problem”.
Last week, preliminary data from the first six months of the surveillance exercise were published by the PHLS in the CDR Weekly. The findings provide insight into the existence of distinct sub-epidemics of infectious syphilis in London; of particular interest is the light it has shed on the role that high-risk behaviours and sexual networks are playing in the continuing evolution of the epidemic.
The enhanced surveillance of syphilis was part of a pilot scheme to improve surveillance of all STIs. Initially, this scheme is being piloted in London and the South East, with a view to rolling it out across England and potentially Wales should it prove successful in improving the surveillance of sexually transmitted infections in the UK.
Enhanced surveillance is intended to improve our ability to monitor changes in those at greatest risk of acquiring an STI.
Between 1 April and 31December 2001 the Communicable Disease Surveillance Centre (CDSC) at the PHLS received 207 reports of infectious syphilis from a total of 27 of 34 genitourinary medicine clinics in London. The majority of reports were received from four clinics.
The overwhelming majority of cases (one hundred and fifty one cases, or 73%) were among gay or bisexual men, with the remaining 56 cases occurring among heterosexuals (twenty of which were in women).
Among heterosexuals only two per cent were known to co-infected with HIV.
In total sixty eight (54%) of the gay men were known to be HIV-positive. Generally, they were older than the HIV-negative gay men, median age 37 years compared with 31 years. In stark contrast to heterosexuals, the majority (75%) of HIV-positive gay men were born in the UK (79% of heterosexuals with syphilis were born outside the UK).
The enhanced surveillance programme collected information about where the gay men had been having sex; 17% of them had used sex-on-premises commercial venues, 6% saunas 4% cruising grounds and 3% the internet. A significant proportion (38%) of the gay men believed they had acquired syphilis through unprotected oral sex. HIV-positive gay men were more likely to present with secondary disease 60% vs 39% and have identified cruising grounds, saunas and the internet as likely places where they may have acquired syphilis.
Where information for gay men was known 87% (116/133) thought that they had acquired their infection in London, while more than half of the heterosexuals (55%) reported having acquired syphilis outside of London.
Many of the awareness raising interventions carried out last year in response to the burgeoning epidemic will be repeated and enhanced this year. The improved data from the enhanced surveillance programmes should facilitate health promoters in deciding which kind of work to undertake and where to best target it.
Preliminary results of enhanced surveillance for infectious syphilis in London. CDR Weekly 31 January 2002.