Evaluating the Performance of Diagnostic Methods for Schistosoma mansoni Against the “Gold” Standard in Amhara National Regional State, Northwest Ethiopia, 2020

Abstract

Background: Schistosoma mansoni is a parasitic worm that can infect humans throughout the world. It is more prevalent in Africa including Ethiopia. Proper detection of Schistosoma mansoni using sensitive diagnostic methods is crucial in the national Schistosoma mansoni prevention and control strategies. However, direct wet mount microscopy with its low sensitivity has been used as a diagnostic technique in Ethiopia. Alternative diagnostic methods are not yet implemented. Therefore, the aim of this study was to evaluate the performance of diagnostic methods for Schistosoma mansoni against the “Gold” standard in Amhara region, Ethiopia. METHODS: A cross-sectional study among 520 school children was conducted from October to December, 2019 in Amhara region. The study participants were selected by using systematic random sampling technique. Stool samples were processed via formol ether concentration, Kato-Katz and spontaneous tube sedimentation techniques. Data was entered into Epi-data version 3.1 and analysis was done using SPSS version 20.0. The sensitivity, specificity, positive predictive value and negative predictive value were calculated against the combined result as “Gold” standard. Strength of agreement of the diagnostic methods was determined by Kappa value. Results: The Overall prevalence of Schistosoma mansoni was 20.2% using a combination of three methods. The prevalence 8.3%, 12.9%, and16.3%, respectively was recorded by using formol ether concentration, Kato-Katz and spontaneous tube sedimentation. The spontaneous tube sedimentation method (81.0%) had better sensitivity as compared to Kato-Katz (63.8%) and formol ether concentration (41.0%) methods in Schistosoma mansoni detection. Conclusion: Spontaneous tube sedimentation was the best method as compared to the other methods to detect Schistosoma mansoni infections. In addition, Kato-Katz method was more sensitive than formol ether concentration method in Schistosoma mansoni detection.