Syphilis seroprevalence among patients attending a sexually transmitted disease clinic in West Bengal, India.

Syphilis is a sexually transmitted disease (STD) and is a major public health concern in India. The trend of syphilis infection was studied in attendees aged 15-49 years in an STD clinic in West Bengal from 2004 to 2008. Blood samples were collected from 250 consecutive patients per year (a total of 1,250 samples over 5 years); the patients attended the STD clinic for 12 weeks (October-December) each year, and the serostatus of syphilis was determined qualitatively with the Venereal Disease Research Laboratory (VDRL) test using serum samples. A quantitative VDRL test was then performed at a dilution of 1:8 using serum samples that yielded positive results in the qualitative VDRL test. Finally, serum samples that yielded positive results in the quantitative VDRL test were also subjected to the Treponema pallidum hemagglutination assay (TPHA). The serum samples that yielded positive results in both the tests were considered syphilis seropositive. All seropositive serum samples from the quantitative VDRL test were also found to be positive results in TPHA. The total seropositivity for syphilis in the STD patients was 8.2% (women, 8.9%; men, 7.7%). Review of the data from 5 consecutive years showed a statistically significant (χ(2) = 9.968, df = 4, P < 0.05) decrease in syphilis positivity from 10.8% (2004) to 3.6% (2008). The results of the study also revealed that the highest seroprevalence was in the 20-24 age group (16.3%), and the lowest seroprevalence was in the 45-49 age group (3.3%). The study indicates the effectiveness of current interventions with a need to focus further on reducing the burden in the 20-24 age group.