More details about malaria resistance

To be infected with the protozoan parasite Plasmodium vivax an interaction between the protein complex on the surface of the red blood cells and the parasite is needed. This complex is named Duffy antigen. P. vivax uses protein PvDVP to connect to this complex. The Duffy antigen system is a blood system, same as AB0. When talking about antigens we are talking about proteins, which are located on the surface of the red blood cells. Duffy positive people have these proteins, and Duffy negative people do not. The majority of the Caucasians are Duffy-positive and many Africans are Duffy-negative.

The P. vivax parasite uses this protein to enter the red blood cell and infects it, which causes the development of the malaria. That is why Duffy-negative individuals, people without the above mentioned antigen, are immune to malaria. The protein, which helps the parasite to infect the red blood cell, is missing and, therefore, there are no infected red blood cells and no development of malaria. Duffy-negative heterozygotes are people, who have only one protein expressed on the surface and are not entirely immune, but show a reduced sensitivity for an infection with the P. vivax parasite. As the result of evolution, the Duffy-negativity in Africa achieved stability in many different ethnic groups, giving people a greater chance of survival, since they could not be infected by the parasite.

Malaria transmission can be reduced by preventing mosquito bites with mosquito nets and insects repellents or by mosquito control by spraying insecticides inside houses and draining standing water where the mosquitoes lay their eggs.

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