Genetic diversity and differentiation in natural Plasmodium falciparum populations inferred by molecular typing of the merozoite surface proteins 1 and 2

Pereira, Fabrício José Tarelho; Cordeiro, José Antônio; Hoffmann, Érika Hellena Esther; Ferreira, Marcelo Urbano

doi:10.1590/s0037-86822002000500018

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…Even though the sample size in this study is too small to ensure a precise determination of genetic diversity of P. falciparum in Honduras (n = 30), results such as high allelic diversity, predominance of K1-type sequences in pfmsp -1, and presence of RO33 genotypes are more similar to distribution patterns worldwide [13,42-44] than those reported in the previous publications [16]. …”

Section: Resultsmentioning

confidence: 48%

Genetic diversity of Plasmodium vivax and Plasmodium falciparum in Honduras

Lopez

Ortiz

Coello

et al. 2012

Malar J

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BackgroundUnderstanding the population structure of Plasmodium species through genetic diversity studies can assist in the design of more effective malaria control strategies, particularly in vaccine development. Central America is an area where malaria is a public health problem, but little is known about the genetic diversity of the parasite’s circulating species. This study aimed to investigate the allelic frequency and molecular diversity of five surface antigens in field isolates from Honduras.MethodsFive molecular markers were analysed to determine the genotypes of Plasmodium vivax and Plasmodium falciparum from endemic areas in Honduras. Genetic diversity of ama-1, msp-1 and csp was investigated for P. vivax, and msp-1 and msp-2 for P. falciparum. Allelic frequencies were calculated and sequence analysis performed.Results and conclusionA high genetic diversity was observed within Plasmodium isolates from Honduras. A different number of genotypes were elucidated: 41 (n = 77) for pvama-1; 23 (n = 84) for pvcsp; and 23 (n = 35) for pfmsp-1. Pvcsp sequences showed VK210 as the only subtype present in Honduran isolates. Pvmsp-1 (F2) was the most polymorphic marker for P. vivax isolates while pvama-1 was least variable. All three allelic families described for pfmsp-1 (n = 30) block 2 (K1, MAD20, and RO33), and both allelic families described for the central domain of pfmsp-2 (n = 11) (3D7 and FC27) were detected. However, K1 and 3D7 allelic families were predominant. All markers were randomly distributed across the country and no geographic correlation was found. To date, this is the most complete report on molecular characterization of P. vivax and P. falciparum field isolates in Honduras with regards to genetic diversity. These results indicate that P. vivax and P. falciparum parasite populations are highly diverse in Honduras despite the low level of transmission.

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Section: Resultsmentioning

confidence: 48%

Genetic diversity of Plasmodium vivax and Plasmodium falciparum in Honduras

Lopez

Ortiz

Coello

et al. 2012

Malar J

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“…Studies conducted to identify the genetic population structure in other apicomplexan parasites, such as Plasmodium falciparum , have demonstrated the presence of multiple infections composed of different genotypes of the parasite population. This has been described with polymorphic proteins, such as MSP‐1, MSP‐2, TRAP, and CS 6 . In contrast, all different isolates contained an msa‐2c coding region with an exact same size of 798 residues.…”

Section: Resultsmentioning

confidence: 99%

msa‐1 and msa‐2c Gene Analysis and Common Epitopes Assessment in Mexican Babesia bovis Isolates

Borgonio¹,

Mosqueda

Genis³

et al. 2008

Annals of the New York Academy of Sciences

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Babesia bovis msa-1 and msa-2c genes belong to the variable merozoite surface antigen gene family. These genes code for antigenic proteins present on the merozoite surface (MSA) and are involved in the parasite invasion to the bovine erythrocyte. Previous studies carried out on MSA-1 have evidenced antigen allelic variation in B. bovis isolates from similar endemic regions, as well as in isolates from different geographic regions of the world (Argentina, Australia, Israel). Studies conducted on MSA-2c, however, have shown that this antigen is widely conserved on isolates from distinct geographic regions. In this study, it was hypothesized that MSA-1 and MSA-2c antigens would contain common epitopes despite the presence of nucleotide sequence differences found in 13 B. bovis isolates and strains collected in geographically distant regions of Mexico. Bioinformatics analysis of the primary structure from DNA fragments derived from PCR amplification, cloning, and sequencing of msa-1 and msa-2c genes from the 13 B. bovis populations revealed that the msa-1 gene product present in the various isolates tested is less conserved among isolates obtained within a similar geographic region in Mexico (51-99.7% sequence identity). Results obtained by immunoblot analysis of B. bovis protein extracts reacted with a monoclonal antibody to MSA-1 42-kDa antigen, conclusively showed cross-reactive common epitopes only in Mexican isolates having high sequence identity (>/=99%, eight isolates). Sequence analysis and multiple alignment of deduced MSA-2c demonstrated a high degree of sequence identity (90-100%) among the Mexican B. bovis isolates and strains. Immunoblot results using a polyclonal antibody to MSA-2c reacted against the protein extracts recognized conserved epitopes in at least nine of the B. bovis isolates. The results obtained in this study agree with those previously reported by other researchers and confirm that, based in sequence identity conservation in Mexican B. bovis isolates and strains so far collected and analyzed, MSA-2c represents an ideal antigen worth evaluating as a vaccine candidate.

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“…This polymorphic gene have been demonstrated as a marker of natural selection, rather than P. falciparum transmission dynamics, and its loci determine the variation in allele frequencies among populations 27,28 . In another regions of Colombia, it has been demonstrated that MAD20 haplotype with a 187-base-pair band is present in all of the samples analyzed, while the K1 and RO33 haplotypes were not found in these regions 29 .…”

Section: Discussionmentioning

confidence: 99%

Artesunate + amodiaquine versus artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in the Colombian Pacific region: a noninferiority trial

Restrepo

Porras-Ramírez

Mendoza

et al. 2012

Rev. Soc. Bras. Med. Trop.

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Introduction: In Colombia, there are no published studies for the treatment of uncomplicated Plasmodium falciparum malaria comparing artemisinin combination therapies. Hence, it is intended to demonstrate the non-inferior efficacy/safety profiles of artesunate + amodiaquine versus artemetherlumefantrine treatments. Methods: A randomized, controlled, open-label, noninferiority (Δ≤5%) clinical trial was performed in adults with uncomplicated P. falciparum malaria using the 28-day World Health Organization validated design/definitions. Patients were randomized 1:1 to either oral artesunate + amodiaquine or artemether-lumefantrine. The primary efficacy endpoint: adequate clinical and parasitological response; secondary endpoints: -treatment failures defined per the World Health Organization. Safety: assessed through adverse events. Results: A total of 105 patients was included in each group: zero censored observations. Mean (95%CI -Confidence interval) adequate clinical and parasitological response rates: 100% for artesunate + amodiaquine and 99% for artemether-lumefantrine; the noninferiority criteria was met (Δ=1.7%). There was one late parasitological therapeutic failure (1%; artemether-lumefantrine group), typified by polymerase chain reaction as the MAD20 MSP1 allele. The fever clearance time (artesunate + amodiaquine group) was significantly shorter (p=0.002). Respectively, abdominal pain for artesunate + amodiaquine and artemether-lumefantrine was 1.9% and 3.8% at baseline (p=0.68) and 1% and 13.3% after treatment (p<0.001). Conclusions: Uncomplicated P. falciparum malaria treatment with artesunate + amodiaquine is noninferior to the artemetherlumefantrine standard treatment. The efficacy/safety profiles grant further studies in this and similar populations.

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Genetic diversity and differentiation in natural Plasmodium falciparum populations inferred by molecular typing of the merozoite surface proteins 1 and 2

Cited by 4 publications

References 11 publications

Genetic diversity of Plasmodium vivax and Plasmodium falciparum in Honduras

Genetic diversity of Plasmodium vivax and Plasmodium falciparum in Honduras

msa‐1 and msa‐2c Gene Analysis and Common Epitopes Assessment in Mexican Babesia bovis Isolates

Artesunate + amodiaquine versus artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in the Colombian Pacific region: a noninferiority trial

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