The Recombinase Polymerase Amplification Test for Strongyloides stercoralis Is More Sensitive than Microscopy and Real-Time PCR in High-Risk Communities of Cusco, Peru

Strongyloidiasis is a neglected, soil-transmitted helminth infection prevalent worldwide. The true burden of strongyloidiasis is unclear due to the lack of sensitive, field-friendly diagnostic tests. PCR tests to detect <i>Strongyloides</i> DNA in stool are sensitive and specific, but the need for expensive equipment limits their use in endemic regions. Isothermal PCR amplification tests are easier to deploy while maintaining sensitivity and specificity. We developed and evaluated a recombinase polymerase amplification lateral flow assay (RPA-LFA) to detect <i>Strongyloides stercoralis</i> in human stool samples. Three hundred stool samples were collected in three communities in the jungle of Cusco, Peru. Samples were tested for <i>S. stercoralis</i> larvae using microscopy (Baermann's, agar plate culture (APC), and rapid sedimentation), real-time PCR, and RPA-LF for <i>Strongyloides</i> DNA. The RPA-LFA showed an analytical limit of detection of 20 pg/µL. The prevalence of <i>S. stercoralis</i> was 27%, 38%, 46.3%, and 46% using microscopy, PCR, microscopy/PCR, and RPA-LFA, respectively. RPA-LFA had a sensitivity and specificity of 59.3% and 58.9%, 66.2% and 71.4%, and 77.2% and 73.1% when microscopy, microscopy/PCR, and real-time PCR were used as the gold standards, respectively. The <i>Strongyloides</i> RPA-LFA is a novel, fast, highly sensitive, and specific molecular method with the potential for deployment in endemic regions.