Abstract
Background: Despite the discovery of artemisinin and artemisinin combination therapies (ACTs), resistance emerged due to single-nucleotide polymorphisms (SNPs) at the Kelch13 propeller domain of Plasmodium falciparum; the predominant parasite causing malaria. This research aimed at surveying the gene responsible for reduced parasite clearance of the first-line antimalarial ACT in Yobe State, Nigeria.
Methods: This study analyzed the blood samples of 300 patients (18-50 years) from 3 different hospitals in Yobe State for malaria using a rapid diagnostic test (malarial strip test). The Giemsa microscopy protocol was performed on the samples that tested positive in order to increase specificity for high parasitemia. Positive samples from microscopy were confirmed by COXIII gene polymerase chain reaction amplification. The fragments of the P. falciparum kelch13 gene encompassing the propeller domains were amplified and sequenced to detect polymorphism.
Results: The result of multiple sequence alignment of 16 successfully sequenced samples performed alongside the reference 3D7 strain revealed nine novel mutations that have not been reported elsewhere. Two were synonymous (S485S and A675A), and seven were non-synonymous (E461V, S485R, D648H, E668Q, S679L, H697Y, and W706M). The genetic diversity parameters obtained in this study indicated non-severe mutations with haplotype diversity [Hd=0.662, D (Tadjima)=-2.16692 and D* (Fu and Li) -3.08435]. Seven different haplotypes were discovered, and the result of the haplotype network demonstrated Hap_1 to be the predominant haplotype in the population.
Conclusion: The absence of the WHO-validated markers may suggest that ACTs are still effective in Yobe.