Antimalarial resistance in Mozambique: Absence of Plasmodium falciparum Kelch 13 (K13) propeller domain polymorphisms associated with resistance to artemisinins

Abstract

Malaria remains one of the most serious public health problem in sub-Saharan Africa and Mozambique is the world's fourth largest contributor, with 4.7% of disease cases and 3.6% of total deaths due to malaria. Its control relies on the fight against the vector and treatment of confirmed cases with antimalarial drugs. Malaria Molecular surveillance is important tool for monitoring the spread of antimalarial drug resistance. A cross-sectional study recruited 450 participants with malaria infection detected by Rapid Diagnostic Test, from three different study sites (Niassa, Manica and Maputo) to collect blood samples on filter papers (Whatman® FTA® cards), between April and August of 2021. Parasite DNA was extracted from all dried blood spot samples using chelex method and Sanger sequenced. SIFT software (Sorting Intolerant From Tolerant) was used, predict whether an amino acid substitution affects protein function. No pfkelch13-mediated artemisinin resistance gene mutation was detected in our study settings. However, non-synonymous mutations were detected at prevalence of 10.2%, 6% and 5% in Niassa, Manica and Maputo, respectively. Most (56.3%) of the reported non-synonymous mutations were due to substitution at the first base of the codon, 25% at the second base and 18.8% at the third base. Additionally, 50% of non-synonymous mutations showed a SIFTscore bellow cut off value of 0.05, therefore, they were predicted to be deleterious. Our results do not show an emergence of artemisinin resistance cases in Mozambique. However, the increased number of novel non-synonymous mutations highlights the relevance of increasing the number of studies focused on the molecular surveillance of ACTs resistance markers, for its early detection.