Genetic profiling of Plasmodium falciparum antigenic biomarkers among asymptomatic pregnant women on intermittent preventive treatment with sulfadoxine-pyrimethamine from southwest Nigeria.

INTRODUCTION

The genetic complexity of Plasmodium falciparum is contributory to the emergence of drug resistant-parasites. Intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) in malaria endemic settings is recommended by WHO. This study evaluated the prevalence of Plasmodium falciparum multidrug resistance-1 gene (Pfmdr-1), genetic diversity of merozoite surface proteins (msp-1, msp-2) and glutamate-rich protein (glurp) among pregnant women with sub-patent parasitaemia from southwest Nigeria.

METHODS

One hundred PCR-confirmed Plasmodium falciparum isolates, collected at first visit-V-1 (n = 52), delivery (n = 31) and cord blood (n = 17), were selected for analysis. The Pfmdr-1 alleles was evaluated using restriction fragment length polymorphism (RLFP), while msp-1, msp-2 and glurp genes were genotyped. Allelic frequency distribution and multiplicity of infection were calculated at p-value ≤0.05.

RESULTS

The Pfmdr-1 (N86/N86Y) combination was detected in 11.8 %, 61.3 % and 58.8 % (p ≤ 0.05) in V-1, Delivery and Cord isolates respectively. The N86Y haplotype was detected only in cord (5.9 %). The allelic frequency distribution for msp-1 was 244 (K1 = 81, MAD20 = 84 and RO33 = 79), and msp-2; 110 alleles, representing 43.6 % (FC27) and 56.4 % (3D7). While glurp expressed 25 alleles, 84 % (V-1), 12 % (delivery) and 4 % (cord), respectively (p ≤ 0.05). The msp-1 and msp-2 recorded higher MOIs than glurp.

DISCUSSION: Genetically diverse P. falciparum strains with Pfmdr-1 mutant alleles were detected in pregnant women with sub-patent parasitaemia in southwest Nigeria, which may reduce IPTp-SP effectiveness. Thus, continuous molecular surveillance of resistant-parasites to sulphadoxine-pyrimethamine and ACTs is essential.