Diagnosis of Schistosomiasis without a Microscope: Evaluating Circulating Antigen (CCA, CAA) and DNA Detection Methods on Banked Samples of a Community-Based Survey from DR Congo

Detection of <i>Schistosoma</i> eggs in stool or urine is known for its low sensitivity in diagnosing light infections. Alternative diagnostics with better sensitivity while remaining highly specific, such as real-time PCR and circulating antigen detection, are progressively used as comp...

Full description

Bibliographic Details
Main Authors: Pytsje T. Hoekstra, Joule Madinga, Pascal Lutumba, Rebecca van Grootveld, Eric A. T. Brienen, Paul L. A. M. Corstjens, Govert J. van Dam, Katja Polman, Lisette van Lieshout
Format: Article
Language:English
Published: MDPI AG 2022-10-01
Series:Tropical Medicine and Infectious Disease
Subjects:
Online Access:https://www.mdpi.com/2414-6366/7/10/315
Description
Summary:Detection of <i>Schistosoma</i> eggs in stool or urine is known for its low sensitivity in diagnosing light infections. Alternative diagnostics with better sensitivity while remaining highly specific, such as real-time PCR and circulating antigen detection, are progressively used as complementary diagnostic procedures but have not yet replaced microscopy. This study evaluates these alternative methods for the detection of <i>Schistosoma</i> infections in the absence of microscopy. Schistosomiasis presence was determined retrospectively in 314 banked stool and urine samples, available from a previous survey on the prevalence of taeniasis in a community in the Democratic Republic of the Congo, using real-time PCR, the point-of-care circulating cathodic antigen (POC-CCA) test, as well as the up-converting particle lateral flow circulating anodic antigen (UCP-LF CAA) test. <i>Schistosoma</i> DNA was present in urine (3%) and stool (28%) samples, while CCA (28%) and CAA (69%) were detected in urine. Further analysis of the generated data indicated stool-based PCR and the POC-CCA test to be suitable diagnostics for screening of <i>S. mansoni</i> infections, even in the absence of microscopy. A substantial proportion (60%) of the 215 CAA-positive cases showed low antigen concentrations, suggesting that even PCR and POC-CCA underestimated the “true” number of schistosome positives.
ISSN:2414-6366