Malaria parasites cause significant morbidity and mortality in their human hosts in areas where it is endemic. The disease’s virulence is dependent largely on the rate of transmission of the parasites. Several factors that contribute significantly to the pathologic characteristics of severe malaria include cytoadherence, which is the adhesion of late-stage-infected erythrocytes to various receptors such as the intercellular adhesion molecule–1 on the vascular endothelium, chondroitin sulfate A in the placenta, and complement receptor (CR)–1 on red blood cells (RBCs; also called “rosetting”). All this leads to microvascular obstructions in various organs.
During the process of intracellular infection of the erythrocytes, the malaria parasites stay in vacuoles. From the vacuoles they export many proteins in the host cell. These protein secretions play a significant role in the level of the virulence of the Plasmodium parasite so that in some individuals malaria episodes progress to severe life-threatening levels. However, amazingly, there are some cases in which these episodes can be self-limiting. This happens mainly because of host genetic factors such as the sickle cell gene.
According to the Centers for Disease Control and Prevention (CDC), the sickle cell gene is caused by a mutation in the single amino acid (valine instead of glutamate at the 6th position) in the beta chain of the hemoglobin gene. Inheriting this mutated gene from both parents can lead to sickle cell disease. Individuals who have this disease tend to have shorter life expectancy. However, those people who are carriers for the sickle cell disease (with one sickle gene and one normal hemoglobin gene, also known as sickle cell trait) tend to have a protective advantage against malaria disease. This is the reason why the frequencies of sickle cell carriers are high in malaria-endemic areas.
Morbidity and mortality entered the world through sin. But God’s grace is amazing!! He even turns adversarial events and situations into building blocks that mitigate the impact of disease among His children.
Learn more about God’s power over disease from the book, The Perfect Prescription, by Reigh Simuzoshya from Amazon.com