Slow parasite clearance, absent K13 gene polymorphisms and observation of amino-acids silent mutations among malaria non-responsive patients: A case study of Kisii County, Kenya.

Abstract

Malaria poses a substantial global health challenge, with the majority of instances concentrated in countries within Sub-Saharan Africa. A variety of antimalarial medications have been created to address the widespread occurrence of Plasmodium falciparum malaria. Since 2004, Artemisinin-based Combination Therapy (ACT) has been the primary treatment for uncomplicated malaria in Kenya. Nevertheless, there is a rising concern attributable to the increasing reports of ACT resistance, particularly in Southeast Asia, and its extension into Africa. In particular, mutations in the Kelch propeller domain on chromosome 13 (Pfk13) have been associated with resistance to ACT. However, our comprehension of mutation prevalence in Africa remains mostly unexplored, especially as slow parasite clearance becomes increasingly prevalent. In this study, we assess polymorphisms in the Plasmodium falciparum Kelch13 propeller gene among malaria non-responsive patients who attended selected hospitals in endemic regions of Kisii County, Kenya. The research found out that all participants experiencing delayed parasite clearance had low parasitemia levels (< 500) after completing the full dose of the ACT drug, as opposed to their parasitemia levels before taking the ACT drugs. The parasite density for all participants in the study who experienced delayed parasite clearance on the first day before taking the ACT drug showed a high mean ± SE of 13951.9 ± 3564.72. In contrast, during the third-day visit, the mean was notably lower at 327.90 ± 41.11, coinciding with their claim of not responding to the drug. Upon sequencing the K13-propeller gene of the isolates and conducting a search for synonymous and non-synonymous mutations in the propeller region of K13, no polymorphism was observed. Surprisingly, upon further investigation into the amino acids of the isolated samples, silent mutations were observed. Continued global surveillance of artemisinin resistance remains crucial, and our findings offer insights into the possible dissemination of resistant parasites in East Africa. These findings suggest that the detection of silent mutations particularly those associated with delayed parasite clearance following ACT, may imply a gradual emergence of ACT-resistant parasites. This warrants additional investigation through in-vitro assays to determine the functional significance of these findings.