Sustained increase in infectious syphilis notifications in Victoria

To the Editor: In Victoria, notifications of infectious syphilis infection (primary, secondary and early latent [< 2 years’ duration]), reported by the Department of Human Services, have increased more than fivefold in the past decade, from 16 in 1995 to 85 in 2004 (Box). An increase in notifications has also been observed in Sydney.1 Whereas previously in Victoria, very few infectious syphilis notifications were reported among men who have sex with men (1 of 16 cases in 1995), in 2004, 63 of a total of 85 cases (74%) were in this group (68% of these were acquired in Victoria).

The Victorian Infectious Diseases Reference Laboratory (VIDRL) conducts testing for sexually transmitted infections (STI) and HIV for three Melbourne sexual health clinics with a high proportion of patients who are men who have sex with men. In 2004, 62 male patients tested positive for infectious syphilis, and 40% of these were HIV-positive. This is similar to the situation in Sydney, where in 2003, 54% of infectious syphilis cases were reported among HIV-positive men who have sex with men.1

Syphilis outbreaks among men who have sex with men have been reported elsewhere in recent years. There was an outbreak of syphilis in this group in Greater Manchester; between 1999 and 2002, and 37% of cases were in HIV-positive men.2 In this population, syphilis infection was associated with unprotected oral sex with high numbers of partners, seeking sexual partners at venues (darkrooms, cruising areas and saunas) and use of drugs (GHB [gamma hydroxybutyrate] and poppers [amyl nitrate]).3 A San Fransisco study in 2000, performed in response to a syphilis outbreak among men who have sex with men, reported that meeting sexual partners through use of the Internet was a factor significantly associated with syphilis infection.4

It is likely that some or all of the factors reported in these outbreaks overseas are contributing to the sustained increased in infectious syphilis notifications in Victoria, but it is important to have local data to ensure interventions are targeted appropriately and cost effectively. In Victoria, responses to the increase in syphilis notifications have already included an alert to general practitioners to encourage men who have sex with men to have syphilis testing and individual counselling, and syphilis testing of men who have sex with men at a popular sex-on-premises venue over a 4-week period. Depending on further studies in this population in Victoria, other responses could include enhancing outreach at Internet chat rooms, intensive counselling of HIV-positive men who have sex with men, and education interventions such as peer-led community-based strategies for countering unsafe sex and substance-use behaviours. Finally, it is vital that interventions are multidisciplinary, collaborative and evidence-based.

Infectious syphilis notifications by year, Victoria

Data from the Notifiable Infectious Diseases Surveillance System Database, Communicable Diseases Section, Victorian Department of Human Services.