​Why people with the hemoglobin genotype AA are more prone to Malaria by Melrowe


According to an assessment carried out at the University of Uyo Teaching Hospital, Nigeria where children were screened for malaria parasitemia -falciparum malaria, blood group, hemoglobin genotypes…

Children with genotype AA (92.3%) were more susceptible to Malaria Parasite than AS (5.1%) and SS (2.6%)

Why people with the hemoglobin genotype AA are more prone to Malaria (updated)

Previously conducted researches have shown that malaria parasites have a high rate of oxygen consumption and ingest large amounts of hemoglobin, during the peripheral blood stage of replication .

This makes the AA blood more conducive and malaria parasite thrives better in it. Reason isn’t far fetched as AA red blood cells have normal hemoglobin (in structure and quantity) meaning a higher oxygen binding capacity -fueling the parasite’s replication process.

Did you know that being a sickle cell carrier (AS) confers some protection against malaria parasite? Well, this is how:

The Malaria Parasite (M.P) has a complex lifecycle and spends part of it in the Red blood cells. In a carrier, the presence of M.P causes the Red blood cell with defective hemoglobin to rupture prematurely making the plasmodium parasite unable to reproduce. During the peripheral blood stage of replication, malaria parasite have a high rate of oxygen consumption and ingests large amounts of hemoglobin.

Further, the polymerization of hemoglobin affects the ability of the parasite to digest it in the first place. Therefore, in areas where malaria is a problem, people’s chances of survival actually increase if they carry sickle cell trait.

Defective hemoglobin(AS) red blood cells adhere to the parasitized red cells much less readily than do the normal red cells(AA)

Abnormal hemoglobin forms can be detected on hemoglobin electrophoresis, a form of gel electrophoresis on which the various types of hemoglobin move at varying speeds. Sickle-cell hemoglobin (HbS) with sickling (HbSC) – the two most common forms – can be identified from there.

Malaria Chemoprophylaxis

The protective effect of sickle-cell trait does NOT apply to people with sickle cell disease-SS (the sufferers) in fact they are more vulnerable to malaria, since the most common cause of painful crises in malarial countries is infection with malaria. It has therefore been recommended that people with sickle-cell disease living in malarial countries should receive anti-malarial chemoprophylaxis for life.