PLASMODIUM FALCIPARUM THE MOST PATHOGENIC OF THE PARASITES THAT CAUSE MALARIA IN HUMANS.
Omair Sohail Ahmed
Student Id : 19251503
Scientific communication skills: Literature review plan
Table of contents
Literature Review
About Plasmodium Falciparum
Growth and Lifecycle
Vaccine development for the disease
Factors that are affecting the progress of the vaccine
Reference list
Abstract
The aim of this study is to review the recent research on the development of vaccines for malaria and the factors affecting the development process. Since the parasite grows in the human host with a complex life cycle the growth and development of the vaccine has been slow. As the parasite develops the most in the initial stage, scientists are working on vaccine that can inhibit the growth of in the early phase. Various factor that affects the development of the vaccine and the recent development would be discussed in detail further.
Literature review:
Plasmodium Falciparum is one of the agents that can cause a type of bacteria which is known for causing malaria. The type of malaria that is caused by Plasmodium Falciparum is malignant tertian malaria (Miller et al. 2002, p.673). This is a unicellular protozoan parasite and the species are transmitted through the bite of the Anopheles mosquito.
This is most pathogenic because it is responsible for causing malaria in about 50 % of humans. Malaria caused by this organism is called Falciparum malaria. There are three common species of this parasite. The first one is known as P.Oval then comes P. Malaria and the last one is the P. vivax (Adams et al. 2001, p.297).
Growth and Lifecycle:
The growth of this parasite begins with the infusion of the female mosquito with the human blood. As the female mosquito sits on the human skin and injects the parasite goes into the human blood through the saliva. From the bloodstream, the organism goes into the liver and gets matured which is called “Schizont or sorority". This is the mother cell of the organism and it multiplies into 3000 daughter cells in a week called Meterozoite (Snow et al. 2005, p.414). The cells invade the human red blood further and form trophozoite. In this way, the multiplication of the cells continues. Within two days the merozoite gets converted into a trophozoite and then they burst into schizont leading to the rupture of the cell..
Vaccine development for the disease :
Scientists have assessed various conditions in order to develop a vaccine that could restrict the growth of the P. Falciparum parasite or could destroy it (Smith et al. 1994, p.2345). The development of the malaria vaccine is based on the activities that can be undertaken at different points based on the life cycle of the parasite.
Scientists trying to develop the vaccine for the parasite of malaria called Plasmodium Falciparum have paid attention to the erythrocytic stage or the stage in which the organism is a Sporozoite (Staalsoe et al. 1999, p.329). They have focussed on this stage because this is the stage in which the parasite grows rapidly. Along with this the scientists are emphasizing on other stages and develop the vaccine for different stages accordingly. The vaccine development of this disease involves stages like an erythrocytic stage, blood stage, TVB vaccine for the rupture stage.
In the earlier times, protection against malaria was done by repeated bites by Plasmodium falciparum‐infected and irradiated but still metabolically active mosquitoes. Recent success using whole‐organism vaccines, the approach has received renewed interest; it was recently reported that repeated injections of irradiated sporozoites increased protection in 80 vaccinated individuals. Other approaches include subunit malaria vaccines, such as the current leading candidate RTS,S (consisting of fusion between a portion of the P.falciparum‐derived circumsporozoite protein and the hepatitis B surface antigen).
Factors that are affecting the progress of the vaccine
The factors that are restricting the progress of the vaccine are:
Lack of understanding- Often the scientists trying to develop a vaccine for the P. Falciparum parasite find it difficult to understand the immune responses that are related to the protection and prevention of the disease (Hayward et al. 2006, p.6). As the malaria parasite is complex scientists have a wide number of approaches.
Environmental factors- Malaria vaccine cannot be applicable for each and every type of environment. The environmental factor is also another factor affecting the development.
Agent factor- This agent is not equally spread in all countries so the development of a vaccine for malaria varies from one country to another.
Financial factor- Development of vaccines for malaria may be difficult in underdeveloped countries as the government is not able to bear expenses that are involved in the development of various stages of vaccines for P.Falciparum parasite causing malaria.
Reference list
Miller, L.H., Baruch, D.I., Marsh, K., and Doumbo, O.K., 2002. The pathogenic basis of malaria. Nature,415(6872), p.673.
Snow, R.W., Guerra, C.A., Noor, A.M., Myint, H.Y. and Hay, S.I., 2005. The global distribution of clinical episodes of Plasmodium falciparum malaria.Nature,434(7030), p.214.
Staalsoe, T., Giha, H.A., Dodoo, D., Theander, T.G. and Hviid, L., 1999. Detection of antibodies to variant antigens on Plasmodium falciparum‐infected erythrocytes by flowcytometry.Cytometry Part A,35(4), pp.329-336.
Hayward, R.E., DeRisi, J.L., Alfadhli, S., Kaslow, D.C., Brown, P.O. and Rathod, P.K., 2000. Shotgun DNA microarrays and stage‐specific gene expression in Plasmodium falciparum malaria.Molecular Microbiology,35(1), pp.6-14.
Smith, T., Schellenberg, J.A., and Hayes, R., 1994. Attributable fraction estimates and case definitions for malaria in endemic. Statistics in medicine,13(22), pp.2345-2358.
Adams, J.H., Blair, P.L., Kaneko, O., and Peterson, D.S., 2001. An expanding EBL family of Plasmodium falciparum. Trends in Parasitology,17(6), pp.297-299.
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