Each year, malaria affects about 400 million people, with a death rate of two to three million. Since the malarial parasite is constantly changing, and effective vaccine has yet to be developed. The sickle cell gene mutation has been shown to have an effective resistance to the malarial parasite for carriers of the gene. Carriers for the sickle cell trait have one sickle cell gene and one normal hemoglobin gene.
The sickle hemoglobin has been shown to impair malaria growth and development because of the change in the hemoglobin. Sickle cell trait does not provide complete protection against the parasite but those infected with P. falciparum are more likely to survive the acute illness. Most of this protection occurs between 2-16 months of life. This relationship was initially discovered when a correlation was found between the distribution of the gene for hemoglobin S and the distribution of malaria in Africa.
In a normal environment, the red cells of people with sickle cell remain normal and only sickle when venous oxygen levels are low. P. falciparum reduces the oxygen tension within the red cells to very low levels when it carries out its metabolism and causes the cells to sickle more readily. The deforming of these cells makes them a target for destruction by phagocytes and they are removed form the circulation and destroyed. The selective sickling of the infected cells reduces the parasite population in people with sickle cell and puts them at a greater chance to survive acute infections caused by malarial parasites. The CDC has determined that the sickle cell trait provides 60% protection against overall mortality caused by malaria.
For those sort of lucky people that have the sickle cell mutation they may be able to have protection against malaria. For people that travel to malarial places their chances are little more slim. Malaria, especially Falciparum malaria, is a medical emergency that requires a hospital stay. Chloroquine is often used as an anti-malarial medication. However, chloroquine-resistant infections are common in some parts of the world. Some common symptoms of this disease is anemia,bloody stools, chills, coma, convulsion, fever, headache, jaundice, muscle pain,nausea, sweating,vomiting.
ReplyDeleteI was just reading an article that was talking of scientists finding new eveidence that resistance to the front-line treatments for malaria is increasing. It was confirmed that resistant strains of the malaria parasite on the border between Thailand and Burma, 500 miles away from previous sites. Do to such said rise, compromises the effort to eliminate malaria. People with sickle cell mutation, may be at greater advantage when it comes to this situation since they have a somewhat protection against malaria.
ReplyDeleteIt is good that carriers of the sickle cell trait are also mostly resistant to malaria caused by P. falciparum. Sickle cell anemia is caused by an abnormal type of hemoglobin called hemoglobin S. which is the protein that carries the oxygen that allows the RBC to take the sickled shape. Another form of malarial resistance not mentioned is the absence of the Duffy RBC antigen. Duffy blood group is the receptor for P. vivax and that the absence of the Duffy blood group on red cells is the resistance factor to P. vivax in persons of African descent.
ReplyDeleteAfrican Americans, those who do not have the sickle cell disease, are also normally resistant to Malaria due to our genetic makeup. Two of the Duffy system genes, Fya and Fyb, act as receptors for malaria. Since blacks are normally Fya-Fyb, their chances of getting malarial are slim to none.
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