Vivax malaria in Mauritania includes infection of a Duffy-negative individual

Nathalie Wurtz,Mohamed Salem Ould Ahmedou Salem,Hervé Bogreau,Khadijetou Mint Lekweiry,Leonardo K Basco,Jean-François Trape,Bruno Pradines,Sébastien Briolant,Ali Ould Mohamed Salem Boukhary,Christophe Rogier,Jamal Eddine Hafid

doi:10.1186/1475-2875-10-336

Abstract

BackgroundDuffy blood group polymorphisms are important in areas where Plasmodium vivax is present because this surface antigen is thought to act as a key receptor for this parasite. In the present study, Duffy blood group genotyping was performed in febrile uninfected and P. vivax-infected patients living in the city of Nouakchott, Mauritania.MethodsPlasmodium vivax was identified by real-time PCR. The Duffy blood group genotypes were determined by standard PCR followed by sequencing of the promoter region and exon 2 of the Duffy gene in 277 febrile individuals. Fisher's exact test was performed in order to assess the significance of variables.ResultsIn the Moorish population, a high frequency of the FYBES/FYBES genotype was observed in uninfected individuals (27.8%), whereas no P. vivax-infected patient had this genotype. This was followed by a high level of FYA/FYB, FYB/FYB, FYB/FYBES and FYA/FYBES genotype frequencies, both in the P. vivax-infected and uninfected patients. In other ethnic groups (Poular, Soninke, Wolof), only the FYBES/FYBES genotype was found in uninfected patients, whereas the FYA/FYBES genotype was observed in two P. vivax-infected patients. In addition, one patient belonging to the Wolof ethnic group presented the FYBES/FYBES genotype and was infected by P. vivax.ConclusionsThis study presents the Duffy blood group polymorphisms in Nouakchott City and demonstrates that in Mauritania, P. vivax is able to infect Duffy-negative patients. Further studies are necessary to identify the process that enables this Duffy-independent P. vivax invasion of human red blood cells.

Highlights

Duffy blood group polymorphisms are important in areas where Plasmodium vivax is present because this surface antigen is thought to act as a key receptor for this parasite
One of the main biological differences between P. vivax and other human malaria parasites is that only P. vivax merozoites use the human Duffy antigen/chemokine receptor (DARC) to invade red blood cells (RBCs) [19,20,21]
In the other ethnic groups (Poular, Soninke and Wolof), only the FYBES/FYBES genotype was found in uninfected patients, whereas the FYA/FYBES genotype was observed in two P. vivax-infected patients, Soninke ethnic

Summary

Introduction

Duffy blood group polymorphisms are important in areas where Plasmodium vivax is present because this surface antigen is thought to act as a key receptor for this parasite. Malaria remains one of the most important parasitic infections in the world, with almost 225 million cases of infection and 0.78 million deaths in 2009, mainly in Africa, Asia and South America [1] It is caused by infection with one or more of five species of Plasmodium parasites. The Duffy antigen was originally identified as a blood group antigen on the surface of RBCs, but it has since been found to be expressed in endothelial cells and neurons [22,23,24] It is implicated in multiple chemokine inflammation, inflammatory diseases, and cancer and might play a role in HIV infection [25,26,27]. The DARC gene ( referred to as FY or Duffy), located on chromosome 1, comprises two exons and produces a protein that has a glycosylated external N-terminal domain, seven transmembrane domains and a short cytosolic C-terminal domain that is not coupled to Gproteins or other known intracellular effectors [28,29,30,31,32,33]

Objectives

Methods

Findings

Discussion

Conclusion