Continental-scale genomic surveillance of Plasmodium falciparum malaria across sub-Saharan Africa with rapid nanopore sequencing

Abstract

In sub-Saharan Africa, continental-scale genomic surveillance of Plasmodium falciparum malaria is needed to track the spread of drug and diagnostic resistance, as well as monitor parasite evolutionary responses to vaccine rollout. Yet continental-scale implementation is hindered by a lack of genomic approaches suitable for local laboratories, and the vastness of the continent. Here, we initiate a decentralised scale-up of P. falciparum genomic surveillance by locally sequencing and analysing 1065 samples across six African countries in one year. We achieve this with a novel nanopore sequencing protocol that is rapid (~5 hr) and cost-effective (<$25 USD/sample), providing surveillance of antimalarial drug resistance genes, hrp2/3 deletions, the vaccine target csp, and the polymorphic gene ama1. We couple this to a laptop-based bioinformatics dashboard that runs offline and displays mapping and variant calling results in real-time. We demonstrate robust sequencing coverage across parasitemia levels and laboratories, accurate identification of antimalarial resistance markers and hrp2/3 deletions; and, with a novel variant caller, sensitive detection of mutations carried by minor clones. Our approach will accelerate genomic surveillance of P. falciparum malaria across sub-Saharan Africa at a time of urgent need.