Relationships between sickle cell trait, malaria, and educational outcomes in Tanzania
The evolutionary link between sickle-cell trait and malaria resistance showed that humans can and do adapt. But are the “bugs” that make us sick evolving as. Although a link between sickle cell disease and resistance to severe malaria is can thus be explained by the survival benefit it has afforded to heterozygotic. PDF | Sickle cell anaemia is a major chapter within haemolytic In this brief review, in keeping with the theme of this journal, we. focus on the close and complex relationship betweeen this blood disease and this infectious disease. The simplest explanation of this fact is that malaria makes the anaemia.
Therefore, by better understanding the tolerance mechanisms, new ways can be figured out to enhance them and also open unexpected avenues for drug development. The researchers have envisioned the journey from infection to illness to recovery as a loop.
Protective Effect of Sickle Cell Trait Against Malaria-Associated Mortality And Morbidity
The infected mosquito bites the person and transfers the malarial parasite into his bloodstream that keeps multiplying inside the cell, hidden from the immune system. The parasite ultimately ruptures its own cellular refuge and, in the process, releases toxins which damage the surrounding tissue. These variables, when plotted on a graph, resembled the above recovery loop.
The plot of number of red blood cells against the number of immature red blood cells revealed that animals had a loop that took them from health to illness and back to health.
Sickle cell carriers are able to fend off malaria. This is clear from the fact that in the African lowlands, where malaria is endemic, the incidence of individuals with sickle cells is high, as compared to the African highlands.
Various explanations have been given for this phenomenon — When the malaria parasite enters the bloodstream of a person with sickle cell trait, the red blood cells break down and do not allow the parasite to continue its lifecycle. In other words, it is not able to get the required conditions necessary for its survival.
How Sickle Cell Protects Against Malaria? - Scientific Animations
The malaria parasite needs haemoglobin to grow. It is not able to continue its growth with the beta haemoglobin released by genes that cause sickle cell disease. Since the oxygen concentration of red blood cells in people with sickle cell trait is low, the malaria parasite reduces it even further, leading to its destruction. The low oxygen concentration has another effect on sickle cells.
Only those individual that inherit two copies of the sickle mutation one from their mother and the other from their father develop sickle cell anemia. If untreated, these individuals have a shorter than normal life expectancy and as such it would be expected that this mutation would be rare in human populations. This is however, far from being the case. Individuals carrying just one copy of the sickle mutation inherited from either the father or mother were known not to develop sickle cell anemia, leading rather normal lives.
However, it was found that these same individuals, said to carry the sickle cell trait, were in fact highly protected against malaria, thus explaining the high prevalence of this mutation in geographical areas where malaria is endemic.
These findings lead to the widespread believe in the medical community that understanding the mechanism whereby sickle cell trait protects against malaria would provide critical insight into developing treatment or a possible cure for this devastating disease, responsible for over a million premature deaths in sub-Saharan Africa. Despite several decades of research, the mechanism underlying this protective effect remained elusive.
Several studies suggested that, in one way or another, sickle hemoglobin might get in the way of the Plasmodium parasite infecting red blood cells, reducing the number of parasites that actually infect the host and thus conferring some protection against the disease.