Plasmodium falciparum multidrug resistance gene-1 polymorphisms in Northern Nigeria: implications for the continued use of artemether-lumefantrine in the region

Abstract

Background: The analysis of single nucleotide polymorphism (SNPs) in drug-resistance associated genes is a commonly used strategy for the surveillance of anti-malarial drug resistance in populations of parasites. The present study was designed and performed to provide genetic epidemiological data of the prevalence of N86Y-Y184F-D1246Y SNPs in Plasmodium falciparum multidrug resistance 1 (pfmdr1) in the malaria hotspot of Northern Nigeria.

Methods: Plasmodium falciparum-positive blood samples on Whatman-3MM filter papers were collected from 750 symptomatic patients from four states (Kano, Kaduna, Yobe and Adamawa) in Northern Nigeria, and genotyped via BigDye (v3.1) terminator cycle sequencing for the presence of three SNPs in pfmdr1. SNPs in pfmdr1 were used to construct NYD, NYY, NFY, NFD, YYY, YYD, YFD and YFY haplotypes, and all data were analysed using Pearson Chi square and Fisher's exact (FE) tests.

Results: The prevalence of the pfmdr1 86Y allele was highest in Kaduna (12.50%, ² = 10.50, P = 0.02), whilst the 184F allele was highest in Kano (73.10%, ² = 13.20, P = 0.00), and the pfmdr1 1246Y allele was highest in Yobe (5.26%, ² = 9.20, P = 0.03). The NFD haplotype had the highest prevalence of 69.81% in Kano (² = 36.10, P = 0.00), followed by NYD with a prevalence of 49.00% in Adamawa, then YFD with prevalence of 11.46% in Kaduna. The YYY haplotype was not observed in any of the studied states.

Conclusion: The present study suggests that strains of P. falciparum with reduced sensitivity to the lumefantrine component of AL exist in Northern Nigeria and predominate in the North-West region.

Keywords: Anti-malarial drug resistance; Haplotypes; P. falciparum; Single nucleotide polymorphisms; pfmdr1.

Fig. 1

A map of Nigeria showing the study sites for the surveillance of pfmdr1 N86Y-Y184F-D1246Y polymorphisms

Fig. 2

Prevalence of pfmdr1 Single Nucleotide Polymorphisms (SNPs) across Four States of Northern Nigeria. The State-wise Distribution of pfmdr1 SNPs at codons 86, 184 and 1246 are shown in A, B and C respectively. Green and red bars in A, B and C (wild and mutant alleles, respectively) are significantly different at codons 86 (² = 10.50, P = 0.02), 184 (² = 13.20, P = 0.00) and 1246 (² = 9.20, P = 0.03) of pfmdr1

Fig. 3

Prevalence of pfmdr1 Single Nucleotide Polymorphisms (SNPs) across North-East and –West Nigeria. The Regional Distribution of pfmdr1 SNPs at codons 86, 184 and 1246 are shown in A, B and C respectively. Green and red bars in A, B and C (wild and mutant alleles, respectively) are not significantly different at codons 86 (² = 1.70, P = 0.19) and 1246 (² = 3.60, P = 0.05) and significantly different at 184 (² = 0.20, P = 0.65) of pfmdr1

Fig. 4

Prevalence of pfmdr1 86-184-1246 Haplotypes across Four States and Two Geopolitical Regions of Nigeria. The Distribution of pfmdr1 Haplotypes across the States and Regions are shown in A and B respectively. Red, Purple, Brown, Ash, Lilac and Empty bars in A and B (pfmdr1 NFD, NYD, YFD, YYD, NFY, NYY, YFY and YYY haplotypes, respectively) are significantly different across the states (² = 36.10, P = 0.00) and not significantly different across the two regions (² = 4.30, P = 0.37)