**5. Duffy and malaria**

The Duffy glycoprotein plays an important role in malaria transmission by acting as the erythroid receptor for *Plasmodium vivax* through binding to the Fy6 epitope (previously known as *P. vivax* Duffy-binding protein (PvDbp)) and for Plasmodium knowlesi. Individuals with Fy(a−b−) phenotype were resistant to parasitic invasion in a study performed on 11 volunteers, whereas those who contracted malaria were Fy(a+) or Fy(b+). Fy6 is present on all erythroid cells with an Fy(a+) or Fy(b+) phenotype. Thus it is absent on red cells with Fy(a−b−) phenotype. In west Africa, individuals with Fy(a−b−) phenotype are found in greater frequency than in areas where *P. vivax* is absent. The protective effect of Fy(a−b−) phenotype does not extend to *P. falciparum* which can infect red cells of all Duffy phenotype [20].
