Treponema pallidum infection rate in patients attending the general hospital of Benguela, Angola

Abstract

Introduction: The objectives of this study were to estimate the rate of infection by Treponema pallidum and co-infection with Human Immunodeficiency Virus (HIV) in individuals attending the General Hospital of Benguela (GHB), Angola, to verify the Rapid Plasma Reagin (RPR) test performance for its diagnosis when compared with other RPR tests, and to compare a rapid treponemal test with the Treponema pallidum hemagglutination assay (TPHA). Methodology: This is a cross-sectional study carried out between August 2016 and January 2017, at the GHB, 546 individuals attending the emergency room, the outpatient service or hospitalized at the GHB were included. All the samples were tested at the GHB with the routine hospital RPR test and a rapid treponemal test. The samples were then transported to the Institute of Hygiene and Tropical Medicine (IHMT) where RPR testing and TPHA testing were performed. Results: The rate of T. pallidum active infection, demonstrated by a reactive RPR and TPHA result, was 2.9%, of which 81.2% corresponded to indeterminate latent syphilis and 18.8% to secondary syphilis. HIV co-infection was detected in 62.5% of individuals diagnosed with syphilis. Past infection, defined as a non-reactive RPR and reactive TPHA test, was diagnosed in 4.1% of individuals. Conclusions: The high rate of syphilis/HIV co-infection emphasizes the urgent requirement for adequate sexually transmitted infections (STIs) screening, prevention and treatment programs. In addition, implementation of quality control measures within RPR testing protocols at GHB are needed, including training for laboratory personnel, adequate equipment and introduction of other rapid testing.