Abstract
Background
The burden of malaria persists in sub-Saharan Africa and the emergence of artemisinin resistance has introduced complexity to control efforts. Monitoring the efficacy of artemisinin-based treatment for malaria is crucial to address this challenge. This study assessed treatment efficacy of artemether-lumefantrine (AL) and genetic diversity of Plasmodium falciparum isolates in a Nigerian population.
Methods
A total of 972 participants presenting at the health centre with clinical symptoms of uncomplicated malaria at the health center were screened for P. falciparum. Enrolled participants spanning three age groups (1–5, 6–14 and > 15 years), were treated with AL and monitored through scheduled check-up visits, clinical and laboratory examinations for 28 days. Parasite clearance and genetic diversity were assessed through polymerase chain reaction (PCR) analysis of merozoite surface proteins (MSP1 and MSP2). The prevalence of drug resistance mutations was assessed by P. falciparum multidrug resistance gene 1 (MDR1) genotyping followed by P. falciparum ubiquitin-specific protease 1 (UBP1) gene sequencing.
Results
The PCR-uncorrected treatment outcome revealed 94.4% adequate clinical and parasitological response (ACPR) and 5.6% late parasitological failure (LPF) rates. After PCR correction, no suspected LPF case was detected and ACPR 67/67 (100%) was achieved in all the individuals. Moreover, a high prevalence of wild-type alleles for MDR1 N86Y (93.7%), and MDR1 D1246Y (87.5%) was observed. Genetic diversity analysis revealed predominant K1 allelic family for MSP1 (90.2%) and FC27 for MSP-2 (64.4%). Estimated multiplicity of infection (MOI) was 1.7, with the highest MOI observed in the 5–15 years age group. UBP1 sequence analysis identified one nonsynonymous E1528D polymorphism at a low frequency (1.6%).
Conclusion
The study demonstrated sustained efficacy of AL for treating uncomplicated P. falciparum malaria. Genetic diversity analysis revealed various allelic types, suggesting occurrences of polyclonal infections. Nonetheless, the detection of a significant UBP1 polymorphism could have future implications for the epidemiology of antimalarial drug resistance in the population.