Background:  Syphilis and HIV operate in epidemiological synergy. Dublin has recently experienced an epidemic of infectious syphilis (primary, secondary or early latent disease). A number of cases were co-diagnosed with HIV. A review of these cases was performed to identify the demographics of syphilis and HIV co-infection in the Dublin cohort.

Methods:  A database was compiled of all cases of syphilis diagnosed through the GUIDE clinic at St.James’s Hospital. The HIV status, age, sex, and mode of acquisition of these cases were documented.

Results:  From January 2000 to September 2003 561 cases of syphilis were diagnosed (356 early infectious); 16% (88) subsequently were re-infected with syphilis and were retreated; 125 (22%) were HIV co-infected; 69 were known to be HIV positive prior to syphilis diagnosis; and 56 (10% of total) were newly diagnosed with HIV. Mean age of the co-infected group was 31.5 years (28 to 71years); 151 patients with syphilis and an initial negative HIV result declined follow-up; 82% of the co-infected group were male. MSM was the risk category for 86% of these men (70% of total). Heterosexual transmission was documented for all of the females. The co-infected group were more likely to present with secondary syphilis. In the same period, 738 new cases of HIV diagnosed were:  52% of cases were heterosexually acquired, 25% in men who have sex with men (MSM), 22% in intravenous drug users (IDU), and the remaining 1% were either blood-borne or unknown mode of acquisition. Among the heterosexual cohort, 68% were female and many of these were migrants from sub-Saharan Africa. Mean age was 36 years (15 to 71). Crude incidence rates of syphilis in HIV infected MSM have increased dramatically in the past 7 years. From 0 per 100,000 in 1999 to 7280 per 100,000 in 2001 and 1553 per 100,000 in 2002. Of the MSM diagnosed HIV positive in this clinic in 2000, 2% were co-diagnosed with syphilis, this rose to 26% in 2001, 29% in 2002, and 23% for 2003 to date.

Conclusions:  Against a background of a syphilis epidemic amongst MSM in Dublin there needs to be heightened awareness about the increased incidence of HIV transmission.

Keywords: HIV; Syphilis; Co-infection