Abstract
BackgroundIn Benin, very few studies have been done on the genetics of Plasmodium falciparum and the resistance markers of anti-malarial drugs, while malaria treatment policy changed in 2004. Chloroquine (CQ) and sulphadoxine pyrimethamine (SP) have been removed and replaced by artemisinin-combination therapy (ACT). The objective of this study was to determine the genetic diversity of P. falciparum and the prevalence of P. falciparum molecular markers that are associated with resistance to CQ and SP in northern Benin seven years after the new policy was instituted.MethodsThe study was conducted in northern Benin, a region characterized by a seasonal malaria transmission. Blood samples were collected in 2012 from children presenting with asymptomatic P. falciparum infections. Samples collected in filter paper were genotyped by primary and nested PCR in block 2 of msp-1 and block 3 of msp-2 to analyse the diversity of P. falciparum. The prevalence of critical point mutations in the genes of Pfcrt (codon 76), Pfmdr1 (codon 86), Pfdhfr (codons, 51, 59 and 108) and Pfdhps (codons 437, 540) was examined in parasite isolates by mutation-specific restriction enzyme digestion.ResultsGenotyping of 195 isolates from asymptomatic children showed 34 msp-1 and 38 msp-2 genotypes. The multiplicity of infection was 4.51 ± 0.35 for msp-1 and 4.84 ± 0.30 for msp-2. Only the codon 51 of Pfdhfr and codon 437 of Pfdhps showed a high mutation rate: I51: 64.4% (57.3; 71.2); G437: 47.4% (40.2; 54.7), respectively. The prevalence of Pfdhfr triple mutant IRN (I51, R59 and N108) was 1.5% (0.3; 3.9), and Pfdhfr/Pfdhps quadruple mutant IRNG (PfdhfrI51, R59, N108, and PfdhpsG437): 0. 5% (0; 2.5). No mutation was found with codon 540 of Pfdhps. Analysis of mutation according to age (younger or older than ten years) showed similar frequencies in each category without significant difference between the two groups.ConclusionsThis study showed a high diversity of P. falciparum in northern Benin with a very low prevalence of resistance markers to CQ and SP that dramatically contrasted with the pattern observed in southern Benin. No influence of age on genetic diversity of P. falciparum and on distribution of the mutations was observed.
Highlights
In Benin, very few studies have been done on the genetics of Plasmodium falciparum and the resistance markers of anti-malarial drugs, while malaria treatment policy changed in 2004
This approach is complicated by genetic diversity of P. falciparum as it influences the acquisition of protective immunity to malaria
The present study was conducted in this locality to determine: (i) the genetic diversity of P. falciparum based on the msp-1 and msp-2 polymorphism; and, (ii) the prevalence of P. falciparum molecular markers that are associated with resistance to CQ and sulphadoxine pyrimethamine (SP) by analysing the point mutations in Pfcrt, Pfmdr1, Pfdhfr and Pfdhps gene using samples from asymptomatic children in northern Benin
Summary
In Benin, very few studies have been done on the genetics of Plasmodium falciparum and the resistance markers of anti-malarial drugs, while malaria treatment policy changed in 2004. Despite intensification of control methods against malaria, multiple factors, including insecticide resistance in anopheline vectors and the emergence and rapid spread of drug-resistant strains, remain of major concern in efforts to control and prevent malaria In this context, adequate vaccine development is a big challenge in malaria control. Asexual blood stage antigens, such as merozoite surface protein-1 (msp-1) and merozoite surface protein-2 (msp-2) are considered prime candidates for the development of malaria vaccine and are suitable markers for the identification of genetically distinct P. falciparum parasite subpopulations [2] These two genes are the basis for determining the multiplicity of infection (MOI) in infected individuals, which is a good indicator of acquired immunity or premunition of populations living in endemic areas, and is correlated to transmission intensity [3,4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
