Journal Article

Performance of real-time polymerase chain reaction and Kato-Katz for diagnosing soil-transmitted helminth infections and evaluating treatment efficacy of emodepside in randomized controlled trials

Lotz, Christian N., Ali, Said M., Schneeberger, Pierre H. H., Mrimi, Emmanuel C., Hattendorf, Jan, Keiser, Jennifer

2025

Overview

The World Health Organization recommends the use of the microscopy-based Kato-Katz thick smear for diagnosing soil-transmitted helminth (STH) infections. Despite its simplicity and cost-effectiveness, the Kato-Katz method faces challenges, including reader subjectivity and reduced sensitivity. Real-time polymerase chain reaction (qPCR) technology offers standardized readouts and higher sensitivity, making it suitable for STH diagnosis and monitoring the treatment efficacy of emodepside within the framework of randomized controlled trials. We evaluated the performance of Kato-Katz versus qPCR for assessing treatment efficacy in terms of cure rates, of single doses of 5, 10, 15, 20, 25 and 30 mg of emodepside compared to 400 mg albendazole. Spearman's rank correlation coefficient examined the correlation between STH eggs per gram in stool samples and qPCR Ct values. Diagnostic sensitivity of qPCR was calculated using a Bayesian latent class modelling approach with data from Ascaris lumbricoides infections. Agreement between Kato-Katz and qPCR at baseline was 93.57% for Trichuris trichiura, and 73.49% for both hookworm and A. lumbricoides. For the latter helminth qPCR demonstrated higher sensitivity (85.00% vs. 47.70%) and slightly lower specificity (93.40% vs. 99.40%) compared to Kato-Katz. We observed a fair to moderate agreement with negative correlation between Ct values and Kato-Katz egg counts. Treatment efficacy, as assessed by qPCR, was lower for all doses of emodepside and albendazole compared to Kato-Katz. Nonetheless, emodepside demonstrated higher cure rates against T. trichiura and A. lumbricoides infections compared to albendazole. Our study confirmed that qPCR is a sensitive diagnostic method for diagnosing STH infections compared to Kato-Katz and serves as a valuable tool for determining treatment efficacy in clinical trials. Furthermore, qPCR confirmed the better treatment efficacy of emodepside compared to albendazole, despite indicating lower cure rates than Kato-Katz.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adolescent / Adult / Albendazole / Albendazole - administration & dosage / Albendazole - therapeutic use / Analysis / Animals / Anthelmintics - administration & dosage / Anthelmintics - therapeutic use / Antiparasitic agents / Ascaris lumbricoides - drug effects / Ascaris lumbricoides - genetics / Ascaris lumbricoides - isolation & purification / Bayesian analysis / Biology and Life Sciences / Child / Child, Preschool / Clinical trials / Correlation / Correlation coefficient / Correlation coefficients / Cost effectiveness / Depsipeptides - administration & dosage / Depsipeptides - therapeutic use / Diagnosis / Disease transmission / Dosage and administration / Drug dosages / Drug therapy / Eggs / Ethanol / Evaluation / Feces - parasitology / Female / Health aspects / Helminthiasis / Helminthiasis - diagnosis / Helminthiasis - drug therapy / Helminthiasis - parasitology / Humans / Infections / Male / Medical research / Medical tests / Medicine and Health Sciences / Medicine, Experimental / Microscopy / Nucleotide sequence / Parasite Egg Count - methods / Parasites / Performance evaluation / Physiological aspects / Polymerase chain reaction / Probability theory / Public health / Real time / Real-Time Polymerase Chain Reaction - methods / Sensitivity / Sensitivity and Specificity / Soil - parasitology / Testing / Treatment Outcome / Trichuriasis - diagnosis / Trichuriasis - drug therapy / Trichuris - drug effects / Trichuris - genetics / Trichuris - isolation & purification / Young Adult