A Novel, Multi-Parallel, Real-Time Polymerase Chain Reaction Approach for Eight Gastrointestinal Parasites Provides Improved Diagnostic Capabilities to Resource-Limited At-Risk Populations

Diagnosis of gastrointestinal parasites has traditionally relied on stool microscopy, which has low diagnostic sensitivity and specificity. We have developed a novel, rapid, high-throughput quantitative multi-parallel real-time polymerase chain reaction (qPCR) platform. Species-specific primers/probes were used for eight common gastrointestinal parasite pathogens: Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale, Giardia lamblia, Cryptosporidium spp., Entamoeba histolytica, Trichuris trichiura, and Strongyloides stercoralis. Stool samples from 400 13-month-old children in rural Ecuador were analyzed and the qPCR was compared with a standard direct wet mount slide for stool microscopy, as were 125 8–14-year-old children before and after anthelmintic treatment. The qPCR showed higher detection rates for all parasites compared with direct microscopy, Ascaris (7.0% versus 5.5%) and for Giardia (31.5% versus 5.8%). Using an enhanced DNA extraction method, we were able to detect T. trichiura DNA. These assays will be useful to refine treatment options for affected populations, ultimately leading to better health outcomes.