Background:
An increase in syphilis has been observed in many major urban areas of the United States, but the current epidemiology of syphilis in lower-prevalence areas has not been studied.

Objective:
To describe the epidemiology and spatial patterns of syphilis among men in Connecticut, a low-prevalence region, in 2004.

Method:
Cross-sectional analysis of health department case reports and field staff interview notes.

Result:
Fifty-five cases of syphilis among men from 25 different towns were reported to the state health department in 2004, representing an increase from recent years (27% since 2003 and 53% since 2002). A majority of cases (82%) were reported among men who have sex with men. Twenty-two percent were co-infected with HIV. A total of 197 sex partners during the infectious period were reported (mean: 3.8, median: 2). Approximately half of these sex partners were not from Connecticut, including 28% from New York City and 20% from other states/countries. The median distance between partners was 48 km. Twenty-three percent of syphilis cases had both local and non-local partners.

Conclusion:
Characteristics of men with syphilis in Connecticut mirror national trends, with recent increases predominantly among MSM, many of whom are also HIV-infected. However, several unique characteristics were also observed, including the dispersal of cases throughout the state and the high proportion of sex partners who reside outside of Connecticut.

Implications:
The epidemiology of syphilis in this low-prevalence region differs from other areas with larger, more focused disease burdens. The observation of a substantial proportion of non-local sex partners suggest that for low prevalence areas, traditional control methods on which we currently rely such as partner notification may not be adequate. Furthermore, the epicenters of high disease burden may well be responsible for many syphilis cases that occur outside such core areas.