My biology textbook says that a person with sickle cell anaemia is less prone to malaria. Why is that so?

I'm guessing that its because the malarial parasite needs human RBCs for completing its life cycle. So are the sickle-shaped RBCs inhospitable to the parasite? In what way exactly?

  • $\begingroup$ The answer to the question of which mine seems to be a duplicate has the following paragraph "Individuals which are heterozygous for HbS alele (which in homozygous state causes sickle-cell anaemia) can catch the parasite, but the chances are bigger, that the infected cells will be phagocytized by macrophages and the parasite will be unable to reproduce in them." $\endgroup$ – user21723 Feb 14 '16 at 13:39
  • $\begingroup$ So I do not understand why chances are greater that the infected cells will be phagocytosed by macrophages. I agree that my query is quite similar, but I am unable to fully comprehend the posted answer. $\endgroup$ – user21723 Feb 14 '16 at 13:40
  • 1
    $\begingroup$ Cells only with HbS (Form of hemoglobin responsible for sickle cell anaemia) have limited lifespan , have changes in shape (due to HbS polymerisation) AND consequently are phagocyted. The heterozygots for HbS have some concentrations of this protein in their RBC, these cells have a bit shortened lifespan, but otherwise can function normally. After infection of such RBC by parasite however, cell has an increased chance of sickling.Sickle cell will probably be phagocytized. Therefore the parazite won't be able to reproduce. Look on an illustration in the original answer, and its article for ref. $\endgroup$ – mpribis Feb 19 '16 at 13:48