Extensive diversity in the allelic frequency of Plasmodium falciparum merozoite surface proteins and glutamate-rich protein in rural and urban settings of southwestern Nigeria

Bassi

et al. 2020

Preprint

Self Cite

Background: Plasmodium falciparum parasites are known to exhibit extensive genetic diversity in areas of high transmission intensity and infected individuals in such communities often harbour several complex mixture of parasite clones with different genetic characteristics. However, in the microenvironment, the extent of genetic diversity of the P. falciparum parasites remain largely unknown. In this study therefore, we investigated the complexity of P. falciparum infections in households, among symptomatic siblings living under the same roof in North-central Nigeria.Methods: Children were enrolled into the study if they were at least two from a household and presented with symptoms of uncomplicated malaria. Clinical malaria was confirmed by light microscopy of Giemsa stained thick and thin blood films. Genomic DNA was isolated from blood spots on filter paper. Molecular characterization of P. falciparum isolates was done by allele-specific nested PCR of the highly polymorphic merozoite surface protein-2 (MSP-2) gene.Results: 93 children from 43 households were enrolled into this study. A total of 26 different MSP-2 alleles were identified from 215 fragments (range: 180-480bp). Majority of the isolates [65.6% (n=61)] were polyclonal infections consisting of 2-6 clones and were significantly more common with the FC27 allelic family (p = 0.036). The multiplicity of infection (MOI) per household ranged from 1.0 to 4.5 while the overall MOI in the study population was 2.31. The pattern of distribution of MSP-2 allele types among the households fell into two categories: households where both MSP-2 allele types (FC27 and 3D7) were present; and households where only one MSP-2 allele type (FC27 or 3D7) was present. Majority of the households [88.4% (n=38)], had both MSP-2 allele types but they were disproportionately distributed among the children while in a few households [11.6% (n=5)], all the children were infected with only one type of MSP-2 allele.Conclusion: Our findings showed that P. falciparum isolates exhibit remarkable degree of genetic diversity in the microenvironment and are composed mainly of multiclonal infections, which is an indication of a high ongoing parasite transmission. This suggests that the microenvironment is an important area of focus for malaria control interventions and for evaluating intervention programmes.

Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 57%

Genetic Diversity and Complexity of Plasmodium Falciparum Infections in the Microenvironment Among Siblings of the Same Household in North-central Nigeria

Bassi

et al. 2020

Preprint

Self Cite

Section: Discussionsupporting

confidence: 93%

Genetic diversity and complexity of Plasmodium falciparum infections in the microenvironment among siblings of the same household in North-Central Nigeria

Bassi

et al. 2020

Preprint

Self Cite

Background Plasmodium falciparum parasites are known to exhibit extensive genetic diversity in areas of high transmission intensity and infected individuals in such communities often harbour several complex mixtures of parasite clones with different genetic characteristics. However, in the micro-environment, the extent of genetic diversity of P. falciparum parasites remain largely unknown. In this study therefore, the complexity of P. falciparum infections in households was investigated among symptomatic siblings, living under the same roof in north-central Nigeria.Methods Children were enrolled into the study if they were at least two from a household and presented with symptoms of uncomplicated malaria. Clinical malaria was confirmed by light microscopy of Giemsa-stained thick and thin blood films. Genomic DNA was isolated from blood spots on filter paper. Molecular characterization of P. falciparum isolates was done by allele-specific nested PCR of the highly polymorphic merozoite surface protein-2 (msp-2) gene.Results Ninety-three children from 43 households were enrolled into this study. A total of 26 different msp-2 alleles were identified from 215 fragments (range: 180-480 bp). Majority of the isolates (65.6% (n=61)) were polyclonal infections consisting of 2-6 clones and were significantly more common with the FC27 allelic family (p = 0.036). The multiplicity of infection (MOI) per household ranged from 1.0 to 4.5 while the overall MOI in the study population was 2.31. The pattern of distribution of msp-2 allele types among the households fell into two categories: households where both msp-2 allele types (FC27 and 3D7) were present; households where only one msp-2 allele type (FC27 or 3D7) was present. Majority of the households (88.4% (n=38)), had both msp-2 allele types but they were disproportionately distributed among the children while in a few households (11.6% (n=5)), all the children were infected with only one type of msp-2 allele.Conclusion These findings showed that P. falciparum isolates exhibit remarkable degree of genetic diversity in the micro-environment and are composed mainly of multiclonal infections, which is an indication of a high ongoing parasite transmission. This suggests that the micro-environment is an important area of focus for malaria control interventions and for evaluating intervention programmes.

“…Allele typing of msp-2 showed that the frequency of fc27 and IC/3d7 allelic families was nearly identical among the isolates; similar to findings from a study in Cambodia [27]. In agreement with previous reports [14,28] and also those reported in a previous studies [29,30,31]. Our results were in contrast with Somé et al finding in Bobo Dioulasso [32].…”

Section: Discussionsupporting

confidence: 91%

Distribution of msp1, msp2 and eba175 Allelic Family According to Hemoglobin Genotype and G6PD Type from Children with Uncomplicated Malaria in Banfora Heath District (Burkina Faso)

Sombié¹,

Sermé

Diawara

et al. 2020

JSRR

Aim: The present study aimed to evaluate the Plasmodium falciparum genetic diversity according to the host hemoglobin and G6PD genetic variants during the course of malaria in infected children aged from 2 to 10 years and living in endemic area in Burkina Faso. Study Design: The study was designed as a longitudinal follow up conducted between May 2015 and February 2016 in Banfora health district, Burkina Faso. Methodology: We included 136 subjects (73 males and 63 females; age range from 2-10 years). Blood thick and thin film was done by capillary blood. Venous blood was collected for DNA extraction. Malaria diagnosis was done by microscopy. Human and parasite DNA were extracted based on Qiagen kit procedure. Then, hemoglobin and G6PD were genotyped by RLFP-PCR while the msp1, msp2 and eba175 genes were typed by a nested PCR. All PCR products were analyzed by electrophoresis on a 1.5-2% agarose gel and alleles categorized according to the molecular weight. Results: The prevalence of hemoglobin type was 19.11% for abnormal hemoglobin and 80.9% for normal hemoglobin carriage. The prevalence of G6PD type was 91.18% for normal and 8.82% for G6PD deficiency carriage, respectively. The prevalence of msp1 allelic families was 81.60%, 80.80% and 67.20% for k1, ro33 and mad20 respectively while for msp2 gene, fc27 and 3D7 allelic family the prevalence was 70.53% and 69.64% respectively. The eba175 allelic families’ distribution showed 77.31% and 40.21% for fcr3 and Camp respectively. There was no difference in multiplicity of infection (MOI) according to hemoglobin genotypes and G6PD types. We found that k1 was the predominant allelic family of msp1 in normal hemoglobin genotype (AA) and normal G6PD type. The mixed infection of eba175 was statistically higher in abnormal hemoglobin (p=0.04). There was no statistical difference between fcr3 and camp prevalence excepted in G6PD deficient type. The polymorphism results showed that the prevalence of 450 bp in fc27 was statistically significantly higher in normal hemoglobin variant carriers (AA) than abnormal hemoglobin carriers (p=2.10 -4)). However, the prevalence of 350 bp in fc27 was statistically higher in normal G6PD than deficient G6PD carriers (p=0.034). Conclusion: Our result showed that the distribution of msp1 and eba75 polymorphism could be influenced by hemoglobin and G6PD variants. These results suggest that hemoglobin and G6PD could influence P. falciparum genetic diversity.