Blood type O defends against severe malaria
Scientists have known for many years that individuals with blood type O do not die from malaria, but definitive research about how this happens has not been released until now.
The plasmodium falciparum parasite species causes severe malaria, which is most commonly found in sub-Saharan Africa. Severe malaria occurs when infected red blood cells coagulate in microvasculature, effectively block the body’s blood flow. This damages tissue by depriving the body of oxygen. These damages result in brain damage, comas and death.
People with blood type A contract malaria, go into a coma and die, whereas people with blood type O do not follow the same fatal pattern.
The study, led by researchers from the Karolinska Institute in Sweden, have found that RIFIN is released by Plasmodium falciparum. The RIFIN protein causes the blood cells to stick together. While RIFIN bonds to blood type A cells with a strong hold, the grip of RIFIN on blood type O cells is weak. This could explain why people with blood type O do not die from severe malaria.
"Our study ties together previous findings," Mats Wahlgren, professor at Karolinska Institute’s Department of Microbiology, Tumour and Cell Biology, said. "We can explain the mechanism behind the protection that blood group O provides against severe malaria, which can, in turn, explain why the blood type is so common in the areas where malaria is common. In Nigeria, for instance, more than half of the population belongs to blood group O, which protects against malaria."
The World Health Organization (WHO) estimates that malaria infects approximately 200 million people each year. As many as 600,000 of those people are children under five years old, many of whom die.