Background. Emergence of artemisinin resistance in Plasmodium falciparum malaria parasites has substantially compromised the efficacy of antimalarial treatments across southeast Asia. The risk of artemisinin resistance emerging or spreading within the African continent will jeopardize past progress made in reducing malaria burden.
Methods. In collaboration with the sentinel sites, more than 2000 samples were collected during the 2018 Dengue outbreak. To investigate ART-R, fifteen blood samples were collected on 18 November 2018 to investigate cases around a malaria symptom persistence in Ndoffane (Kaolack) and surrounding healthcare sentinel sit centers surrounding areas. The malaria parasite artemisinin resistance gene marker PfKelch13 was sequenced. An isolate with the PfKelch13R515K mutant was detected in Kaolack, Senegal. Genomeediting using CRISPR-Cas9, was used to create transgenic lines carrying single nucleotide polymorphism. These lines were tested for their in vitro phenotype using the standard Ring Survival assay RSA0-3h.
Results. We show that PfKelch13R515K confers increased in vitro RSA0-3h survival while PfKelch13R622I a mutant previously associated with delayed in vivo parasite clearance in Ethiopia does not confer elevated RSA0-3h survival.
Conclusions. We report for the first time the functional significance of the PfKelch13R515K mutation previously identified in SE Asia. We have demonstrated the impact of combined genomic surveillance with complementary Plasmodium falciparum genome editing to assess the functional role of mutations associated with recrudescence or treatment failure to artemisinin-based combination therapies.