Sensitive and modular amplicon sequencing of diversity and resistance for research and public health.

Background: Targeted amplicon sequencing is a powerful and efficient tool for interrogating the genome, generating actionable data from infections to complement traditional malaria epidemiology. For maximum impact, genomic tools should be multi-purpose, robust, sensitive, and reproducible.

Methods: We developed, characterized, and implemented MADHatTeR, an amplicon sequencing panel based on Multiplex Amplicons for Drug, Diagnostic, Diversity, and Differentiation Haplotypes using Targeted Resequencing, along with a bioinformatic pipeline for data analysis. Additionally, we introduce an analytical approach to detect gene duplications and deletions from amplicon sequencing data. Laboratory control and field samples were used to demonstrate the panel's high sensitivity and robustness.

Results: MADHatTeR targets 165 highly diverse loci, focusing on multiallelic microhaplotypes, key markers for drug and diagnostic resistance (including duplications and deletions), and and potential vaccine targets. The panel can also detect non- species. MADHatTeR successfully generated data from low-parasite-density dried blood spot and mosquito midgut samples, and detected minor alleles at within-sample allele frequencies as low as 1% with high specificity in high-parasite-density dried blood spot samples. Gene deletions and duplications were reliably detected in mono- and polyclonal controls. Data generated by MADHatTeR were highly reproducible across multiple laboratories.

Conclusions: The successful implementation of MADHatTeR in five laboratories, including three in malaria-endemic African countries, showcases its feasibility and reproducibility in diverse settings. MADHatTeR is thus a powerful tool for research and a robust resource for malaria public health surveillance and control.