Background:
After the resurgence of primary and secondary (P&S) syphilis in men who have sex with men (MSM) in cities throughout the US between 2000-2003, several cities have noted recent declines in P&S syphilis reports. Chicago reported declines in MSM P&S syphilis in 2003-2004, but has experienced a resurgence in 2005.

Objective:
To describe recent changes in the epidemiology of P&S syphilis among MSM in Chicago.

Method:
Surveillance data for cases of P&S syphilis between 2001-2005 were analyzed. Data for 2005 is provisional.

Result:
Between 2001-2002 60% of P&S syphilis cases in Chicago were among MSM. Cases peaked in 2002 with 211 MSM cases, but declined to 162 (23% decrease) by 2004, when MSM comprised 54% of total cases. The 203 provisional cases reported in 2005 among MSM represents a 25% increase over 2004, with MSM comprising 75% of 2005 P&S morbidity reports. MSM cases in 2005 were similar to 2004 with respect to geographic location, age (36 vs. 35 years), race/ethnicity, and number of median sex partners(3). Interview data was available for 95% (346/365) of MSM with P&S syphilis reported in 2004 and 2005. MSM reported with P&S syphilis in 2005 versus in 2004 were more likely to meet their partners via the internet (57% vs. 40%) and less likely meet their partners at bathhouses (20% vs. 27%), but there was no difference with respect to reporting anonymous partners(63% vs. 60%).

Conclusion:
A resurgence of P&S syphilis among MSM in Chicago in 2005 occurred despite the implementation of a targeted syphilis social-marketing campaign. These data highlight the need for effective and innovative intervention strategies for syphilis control in MSM.

Implications:
Community involvement in syphilis control are needed. Public awareness should be raised through mass media and enhanced education/training for public and private health care providers.