Genetic Diversity of the Plasmodium falciparum Glutamate-Rich Protein R2 Region Before and Twelve Years after Introduction of Artemisinin Combination Therapies among Febrile Children in Nigeria

Abstract

The genetic diversity of glutamate-rich protein () R2 region in isolates collected before and 12 years after the introduction of artemisinin combination treatment of malaria in Osogbo, Osun State, Nigeria, was compared in this study. Blood samples were collected on filter paper in 2004 and 2015 from febrile children from ages 1-12 years. The R2 region of the gene was genotyped using nested polymerase chain reaction and by nucleotide sequencing. In all, 12 alleles were observed in a total of 199 samples collected in the two study years. The multiplicity of infection (MOI) marginally increased over the two study years; however, the differences were statistically insignificant (2004 samples MOI = 1.23 versus 2015 samples MOI = 1.47). Some alleles were stable in their prevalence, whereas two alleles, VIII and XI, showed considerable variability between both years. This variability was replicated when sequences from other regions were compared with ours. The expected heterozygosity () values ( = 0.87) were identical for the two groups. High variability in the rearrangement of the amino acid repeat units in the R2 region were observed, with the amino acid repeat sequence DKNEKGQHEIVEVEEILPE more prevalent in both years, compared with the two other repeat sequences observed in the study. The parasite population characterized in this study displayed extensive genetic diversity. The detailed genetic profile of the R2 region has the potential to help guide further epidemiological studies aimed toward the rational design of novel chemotherapies that are antagonistic toward malaria.

Systematic review of Plasmodium falciparum and Plasmodium vivax polyclonal infections: Impact of prevalence, study population characteristics, and laboratory procedures

“…By CE, fragments differing as little as 3 base pairs in size can be distinguished. In contrast, when binning using gels, resolution might be as low as 50 base pairs [ 35 ]. Previous studies comparing the two methods directly showed that CE yields higher multiplicity [ 31 , 32 ].…”

Molecular surveillance and temporal monitoring of malaria parasites in focal Vietnamese provinces

“…Resistance to artemisinin is well documented in Vietnam, Western Cambodia and Thai-Myanmar borders [ 7 ]. Since a significant proportion of the Vietnamese population lives in malaria endemic areas, where resistant phenotypes have been reported, studies to decipher the genetic diversity and multiplicity of infections (MOI) of P. falciparum are essential to understand the intensity of transmission, epidemiological patterns and virulence of the parasites and, in particular, to evaluate measures aimed at malaria control [ 8 – 11 ].…”

Genetic polymorphism of Plasmodium falciparum msp-1, msp-2 and glurp vaccine candidate genes in pre-artemisinin era clinical isolates from Lakhimpur district in Assam, Northeast India

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