Seroprevalence of syphilis in human immunodeficiency virus patients with special reference to diagnostic utility of rapid plasma reagin test

Abstract

Background: Syphilis is a sexually transmitted infection caused by Treponema pallidum. High prevalence of syphilis was observed among human immunodeficiency virus (HIV)-positive patients. Atypical serological responses such as high antibody titers leading to frequent false-negative reactions have been reported with nonspecific treponemal tests. Simultaneous infection of syphilis and HIV in pregnant women increases the risk of HIV transmission from mother-to-child. Aim: The aim of the study was to assess the seroprevalence of syphilis in HIV patients including pregnant women and to know the efficiency of serological tests in detecting syphilis among HIV patients. Materials and Methods: The present study was a hospital-based cross-sectional study conducted among 500 HIV-reactive patients, including 100 HIV-reactive pregnant women attending the Outpatient Department of Dermatology, Venereology and Leprosy in a tertiary care center were enrolled in the study and were tested for the presence of syphilis using rapid plasma reagin (RPR) and T. pallidum hemagglutination assay (TPHA). Results: Among 500 samples, 58 (11.65%) were positive for syphilis. The most common age group was 30–39 years. Both RPR and TPHA were reactive in 25% of cases, TPHA reactive in 60.2% of cases, and only RPR reactive in 14.7% of cases. Seropositivity among pregnant women was 7%. The sensitivity and specificity of RPR test was 29.3% and 97.7%, respectively, in comparison with TPHA. Positive and negative predictive values of the same were found to be 62.9% and 91.3%, respectively, compared to TPHA. Conclusion: In all symptomatic and asymptomatic cases of syphilis, both RPR and TPHA should be performed for laboratory diagnosis of syphilis. It is advocated that all patients with newly diagnosed HIV should be suggested for syphilis serology and vice versa.