Modelling the drivers of the spread of gene deletions in sub-Saharan Africa.

Rapid diagnostic tests (RDTs) have transformed malaria diagnosis. The most prevalent RDTs detect histidine-rich protein 2 (PfHRP2). However, gene deletions yielding false-negative RDTs, first reported in South America in 2010, have been confirmed in Africa and Asia. We developed a mathematical model to explore the potential for RDT-led diagnosis to drive selection of -deleted parasites. Low malaria prevalence and high frequencies of people seeking treatment resulted in the greatest selection pressure. Calibrating our model against confirmed -deletions in the Democratic Republic of Congo, we estimate a starting frequency of 6% -deletion prior to RDT introduction. Furthermore, the patterns observed necessitate a degree of selection driven by the introduction of PfHRP2-based RDT-guided treatment. Combining this with parasite prevalence and treatment coverage estimates, we map the model-predicted spread of -deletion, and identify the geographic regions in which surveillance for -deletion should be prioritised.