Background:
Despite rapidly instituted outbreak control efforts, prevalence of syphilis in Los Angeles County remains high especially among MSM, many of whom are also HIV positive.

Objective:
To evaluate observed trends and level of high-risk behaviors and HIV seroprevalence among early syphilis cases.

Method:
Trends in HIV seroprevalence and risk behaviors and their deviation from a zero slope were assessed for six month interval between January 2001 and June 2005 using the Cochran-Armitage test for trends. Differences in HIV seroprevalence and high-risk behaviors between MSM and heterosexual early syphilis cases were assessed.

Result:
Between January – June 2001 and January – June 2005, HIV co-infection decreased from 72.7% to 65.2% among MSM (p=0.21), where as it increased from 5.4% to 7.7% among heterosexuals (p=0.67) although the decline was not statistically significant. Statistically significant decline in condom use from 42.3% to 29.6 (X2 test for trend = -1.9, p=<0.05) among MSM and from 32.3% to 16.7% (X2 test for trend = -1.8, p<0.05) among heterosexuals were observed. In contrast the frequency of anonymous sex decreased among MSM from 75.7% to 73.6% (X2 test for trend = -0.36, p=0.71), and among heterosexuals from 45.1% to 40.8% (X2 test for trend = -0.42, p=0.67), although statistical differences were not observed. Nonetheless, MSM with early syphilis were twenty six times more likely to be HIV positive than heterosexuals (OR=26.8; 95%CI 13.2 – 54.6).

Conclusion:
Five years into the epidemic, lack of substantial reduction in high risk behaviors like anonymous sex and condom non-use and HIV co-infection among early syphilis cases underscore the need for more effective prevention and risk reduction efforts.

Implications:
Continued monitoring of risk behaviors (behavioral surveillance) among those who are reported with STDs is critical for evaluating trends in sexual practices as well as the impact of prevention efforts.