Evolution of Pfdhps and Pfdhfr mutations before and after adopting seasonal malaria chemoprevention in Nanoro, Burkina Faso

Abstract

Seasonal Malaria Chemoprevention consisting of monthly administration of amodiaquine/sulfadoxine-pyrimethamine to children aged 3-59 months during the transmission season could promote SP-resistance. Mutations in dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes were assessed before and after SMC adoption in Burkina Faso. A total of 769 dried blood spots were selected from studies conducted in Nanoro, Burkina Faso, between 2010 and 2020. Of those, 299 were pre-SMC (2010-2012) and 470 were post-SMC-samples. Pfdhps and Pfdhfr genes were PCR-amplified and sequenced. A systematic review/meta-analysis of published studies conducted in Burkina Faso (2009-2023) was additionally performed. In Nanoro, the prevalence of Pfdhfr triple mutations (CIRNI) rose from 43.6% pre-SMC to 89.4% post-SMC (p < 0.0001). There was no mutation in Pfdhfr 164 and Pfdhps 540; Pfdhps A437G mutation increased from 63.9% (2010-2012) to 84.7% (2020) (p < 0.0001). The VAGKGS haplotype was 2.8% (2020). Pfdhfr/Pfdhps quintuple mutant IRN-436A437G rose from 18.6% (2010-2012) to 58.3% (2020) (p < 0.0001). Meta-analysis results from Burkina Faso showed an increase in mutations at Pfdhfr N51I, C59R, S108N, and Pfdhps A437G after SMC adoption. Post-SMC, the pyrimethamine-resistance marker prevalence increased, while the sulfadoxine-resistance marker prevalence remained stable. Detection of emerging PfdhpsVAGKGS haplotypes in 2020 underscores the importance of continuous SP-resistance monitoring.

Keywords: Pfdhfr; Pfdhps; Plasmodium falciparum; Burkina Faso; SMC.

Fig. 1

Temporal trends in prevalence of mutant, mixed and wild-type alleles of Pfdhfr and Pfdhps in 2010–2012, 2018 and 2020 in Nanoro, Burkina Faso. (a) Pfdhfr codons (2010–2012: N = 280; 2018: N = 238; 2020: N = 227); (b) Pfdhps codons (2010–2012: N = 280; 2018: N = 236; 2020: N = 216).

Fig. 2

Prevalence of mutations at codons Pfdhfr and Pfdhps from previous studies conducted between 2009 and 2023 in Burkina before and after implementing SMC. The prevalence rates of various mutations documented in each study were graphed and illustrated by individual data points. Two distinct groups were delineated: one comprising studies conducted before the implementation of SMC (before 2014) and the other encompassing studies conducted after the adoption of SMC (after 2014). Each group’s median (with the interquartile) was compared using a non-parametric test (Wilcoxon Mann–Whitney test).

Fig. 3

Linkage disequilibrium (LD) analysis of Pfdhps SNPs related to the mutations I431V, S436A, A437G, A581G and A613S. The dark red indicates a strong statistically significant (p < 0.001) linkage. Yellow indicates that no linkage is present. Orange indicates the presence of the linkage with a statistically significant (p < 0.05) linkage.