Allelic Diversity of <i>MSP1</i> Gene in <i>Plasmodium falciparum</i> from Rural and Urban Areas of Gabon

Abstract

The present study determined and compared the genetic diversity of Plasmodium falciparum strains infecting children living in 2 areas from Gabon with different malaria endemicity. Blood samples were collected from febrile children from 2008 to 2009 in 2 health centres from rural (Oyem) and urban (Owendo) areas. Genetic diversity was determined in P. falciparum isolates by analyzing the merozoite surface protein-1 (msp1) gene polymorphism using nested-PCR. Overall, 168 children with mild falciparum malaria were included. K1, Ro33, and Mad20 alleles were found in 110 (65.5%), 94 (55.9%), and 35 (20.8%) isolates, respectively, without difference according to the site (P>0.05). Allelic families’ frequencies were comparable between children less than 5 years old from the 2 sites; while among the older children the proportions of Ro33 and Mad20 alleles were 1.7 to 2.0 fold higher at Oyem. Thirty-three different alleles were detected, 16 (48.5%) were common to both sites, and 10 out of the 17 specific alleles were found at Oyem. Furthermore, multiple infection carriers were frequent at Oyem (57.7% vs 42.2% at Owendo; P=0.04) where the complexity of infection was of 1.88 (±0.95) higher compared to that found at Owendo (1.55±0.75). Extended genetic diversity of P. falciparum strains infecting Gabonese symptomatic children and high multiplicity of infections were observed in rural area. Alleles common to the 2 sites were frequent; the site-specific alleles predominated in the rural area. Such distribution of the alleles should be taken into accounts when designing MSP1 or MSP2 malaria vaccine.

Genetic Polymorphism ofmsp1 andmsp2 inPlasmodium falciparumIsolates from Côte d’Ivoire versus Gabon

“…Considering msp 1 gene only, it was shown that the relation between the complexity and age could change according to the site with a trend of increase in rural area and decrease in urban area [ 40 ]. In our study, we observed a significant decrease of COI with age for msp 1 gene in Côte d'Ivoire.…”

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

“…The assemblage of baseline data for these polymorphic biomarkers in the parasite population from different geographical regions and different levels of malaria transmission in urban and rural areas are essential tools for the current efforts on malaria control strategies in sub-Saharan Africa [ 20 , 21 ]. Significantly and probably more pertinent to this study are anecdotal reports stating that the patterns of infection and disease severity differs between rural and urban areas [ 22 , 23 ]. If so, how would this affect control programmes or institution of national treatment guidelines between rural and urban areas among infected patients?…”

Dynamics of Plasmodium falciparum genetic diversity among asymptomatic and symptomatic children in three epidemiological areas in Cote d’Ivoire

“…This could suggest that the genotypes found were common regardless of the severity of the malaria infestation. In contrary, the high parasitemia was linked to the heterogeneity of Plasmodium strains as previously reported [9,21,43]. However, some authors did not find any association between parasitemia and COI [15,44,45].…”

“…Thirty-eight Pfmsp1 and 27 Pfmsp2 alleles were found. [21]. In Benin in the coastal departments and Ouémé from May to August 2011, 25 Pfmsp1 and 28 Pfmsp2 alleles were observed [22] while in Cameroon in the localities of the eastern slope of Mount Cameroon, 34 alleles of the Pfmsp1 family were reported [23].…”

“…In addition, the prevalence of MIs was higher in the rainy season and in the dry season) respectively for Pfmsp1 and Pfmsp2. Indeed, the level of transmission can influence the occurrence of mixed infections; polyclonal infections being more frequent in areas of intense malaria transmission [21,46].…”