ACKR1 and malaria: The invasion of erythrocytes by P.vivax merozoites requires interaction with the Duffy antigen receptor for chemokines (DARC) with Duffy-negative individuals considered to be naturally resistant to this human malaria parasite.58 The high proportion of Duffy-negative people in West and Central Africa has long be viewed as the most plausible explanation of the rarity of P.vivax malaria in those geographical areas.