Polymorphisms in Plasmodium falciparum dihydropteroate synthetase and dihydrofolate reductase genes in Nigerian children with uncomplicated malaria using high-resolution melting technique

Onikepe A Folarin,Christian T Happi,Fehintola V Ajogbasile,Adeyemi T Kayode,Akintunde Sowunmi,Jessica N Uwanibe,Paul E Oluniyi,Dyann F Wirth,Philomena J Eromon,Kazeem Akano

doi:10.1038/s41598-020-80017-6

Abstract

In 2005, the Nigerian Federal Ministry of Health revised the treatment policy for uncomplicated malaria with the introduction of artemisinin-based combination therapies (ACTs). This policy change discouraged the use of Sulphadoxine-pyrimethamine (SP) as the second-line treatment of uncomplicated falciparum malaria. However, SP is used as an intermittent preventive treatment of malaria in pregnancy (IPTp) and seasonal malaria chemoprevention (SMC) in children aged 3–59 months. There have been increasing reports of SP resistance especially in the non-pregnant population in Nigeria, thus, the need to continually monitor the efficacy of SP as IPTp and SMC by estimating polymorphisms in dihydropteroate synthetase (dhps) and dihydrofolate reductase (dhfr) genes associated with SP resistance. The high resolution-melting (HRM) assay was used to investigate polymorphisms in codons 51, 59, 108 and 164 of the dhfr gene and codons 437, 540, 581 and 613 of the dhps gene. DNA was extracted from 271 dried bloodspot filter paper samples obtained from children (< 5 years old) with uncomplicated malaria. The dhfr triple mutant I51R59N108, dhps double mutant G437G581 and quadruple dhfr I51R59N108 + dhps G437 mutant haplotypes were observed in 80.8%, 13.7% and 52.8% parasites, respectively. Although the quintuple dhfr I51R59N108 + dhps G437E540 and sextuple dhfr I51R59N108 + dhps G437E540G581 mutant haplotypes linked with in-vivo and in-vitro SP resistance were not detected, constant surveillance of these haplotypes should be done in the country to detect any change in prevalence.

Highlights

In 2005, the Nigerian Federal Ministry of Health revised the treatment policy for uncomplicated malaria with the introduction of artemisinin-based combination therapies (ACTs)
A total of 271 children from Adamawa (50), Bayelsa (45), Imo (82), Kwara (45) and Sokoto (49) states with uncomplicated falciparum malaria were considered in this analysis
51, 59, 108 and 164 of dhfr gene and codons 437, 540, 581 and 613 of dhps gene and estimated the prevalence of dhfr + dhps combined mutant haplotypes in 271 parasites obtained from children (< 5 years) children with uncomplicated falciparum malaria in Nigeria 10 years after treatment policy was changed to ACTs

Summary

Introduction

In 2005, the Nigerian Federal Ministry of Health revised the treatment policy for uncomplicated malaria with the introduction of artemisinin-based combination therapies (ACTs). In 2005, the Nigerian Federal Ministry of Health (FMoH) revised the treatment policy for uncomplicated malaria with the introduction of artemisinin-based combination therapies (ACTs)[1] This treatment policy change discouraged the use of Chloroquine (CQ) and Sulphadoxine-pyrimethamine (SP) as the first-line and second-line treatment of uncomplicated falciparum malaria, respectively. Providing evidence for the continued use of SP as IPTp and SMC in the context of SP resistance in Africa requires constant epidemiological surveillance of parasite resistance levels by monitoring polymorphisms in genes associated with SP resistance. Point mutations such as S 436A, A437G, K540E, A581G and A. The quintuple mutation in P. falciparum parasites, i.e., triple dhfr mutations of I51, R59, and N108, plus double dhps mutations of G437, and E540 (I51R59N108G437E540) has been strongly linked with reduced SP efficacy as IPTp, reduced parasite clearance ability in asymptomatic pregnant women and shortened post-treatment prophylactic a ctivity[7,8,9]

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Methods

Conclusion