03238nas a2200301   4500000000100000008004100001260003700042653002100079653002000100653003100120653002700151653002500178100001700203700001400220700001500234700001200249700001200261700001500273700001100288700001300299700001200312245016700324856007900491300000900570490000700579520233600586022001402922       2025                            d  bPublic Library of Science (PLoS)10aSchistosomiasis 10aDisease mapping10aCost-effectivines Analysis10aMathematical modelling10aDisease surveillance1 aChevalier JM1 aGrantz KH1 aGirdwood S1 aKepha S1 aRamos T1 aNichols BE1 aKhan S1 aHingel S1 aRosa BA00aThe impact and cost of a new rapid diagnostic test for school-based prevalence mapping and monitoring and evaluation surveys of schistosomiasis: A modelling study  uhttps://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0013071  a3-140 v193 a<p><strong>Background </strong>In endemic communities where the prevalence of Schistosomiasis is ≥ 10%, annual preventive chemotherapy is recommended. Traditional sampling methods determine infection prevalence through district-level surveys in school-aged-children (SAC). Recently, an alternative sampling strategy - the Schistosomiasis Practical and Precision Assessment (SPPA) protocol - was developed to aid in targeting treatment to the sub-district level. A prototype circulating anodic antigen rapid diagnostic test (CAA RDT) could avoid the pitfalls associated with current microscopy techniques and therefore be better suited to support precision-mapping.</p>

<p><strong>Methodology </strong>We modelled the ability of a CAA RDT to correctly classify sub-district prevalence above or below the 10% threshold in simulated districts under alternative sampling strategies. Each district (10 sub-districts/district) had varying mean prevalence and prevalence distributions. Test sensitivity (60–100%) and specificity (95–100%) of the CAA RDT was varied. We then determined the associated survey costs for prevalence mapping or monitoring and evaluation for each sampling strategy using the CAA RDT compared to microscopy.</p>

<p><strong>Results </strong>The CAA RDT cost/SAC was US$12.14, which was similar to Kato-Katz (US$13.23/SAC) using traditional sampling. Sampling with the CAA RDT cost the least when conducting SPPA sampling or M&amp;E, or when both Kato-Katz and urine filtration were required. High specificity of the CAA RDT was a key determinant of performance and a test with 100% specificity and 85% sensitivity correctly classified the most sub-districts (87%) under SPPA sampling. SPPA sampling generally led to less under- and overtreatment of sub-districts compared to traditional sampling.</p>

<p><strong>Conclusions</strong> A CAA RDT with high specificity will lead to similar treatment success at lower costs, under either sampling strategy, as compared to Kato-Katz and urine filtration. The CAA RDT could be a valuable diagnostic tool for determining schistosomiasis prevalence and could better support precision mapping strategies through reduced costs, thereby improving mass drug administration and aiding programmes to eliminate schistosomiasis as a public health problem.</p>
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