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Malaria vaccines
by Tony Holder
What is malaria? ...
The problem of malaria is massive. ... Over forty percent of the worlds population is at risk from the disease and the incidence of malaria is increasing as the disease moves back into areas from which it had once been eliminated. ... Malaria is the most important parasitic disease. ... The malaria parasite is a single cell, but despite this apparent simplicity it has a complex parasitic life style, spending part of its life in a mosquito and part in a larger animal. There are different sorts of malaria parasites that have adapted to life in a variety of animals, including lizards, birds, small mammals like rats and larger animals like humans. However, only one type of mosquito (the Anopheles mosquito) can become infected by the malaria parasite. ... As soon as the malaria parasite is in the bloodstream of the human body it needs to hide within a cell to avoid the bodys defence system. ... It is this stage of the parasites life cycle that is responsible for the disease of malaria. ... This is the basis of vaccination against disease. Vaccination has proved to be a very effective way to deal with some bacteria and viruses, for example whooping cough, tetanus, poliomyelitis and measles. ... Vaccination therefore seeks to prime the defences so that they are more prepared and can be called upon more quickly to deal with an attack from the microorganism.
How can the deadly cycle of infection and transmission of the malaria parasite be controlled? ... It is known that people who live in areas where malaria is a major problem do eventually develop a good defence to the parasite after repeated attacks of malaria. ... This would be particularly important as a way of protecting very young children in malarious areas, or visitors (such as tourists and military personnel) who would be very vulnerable to an attack of malaria. ... This means that the defences that might be effective against one form will not be effective against another and a number of vaccination strategies have therefore been developed. ... A third approach is to try to prime the immune system to recognise liver cells which become infected as being "foreign" so that specialised cells of the immune system that detect modified or abnormal cells could destroy them, and in yet another vaccination strategy the aim is to stop the parasite infecting the mosquito, thereby preventing it being spread to other humans. ... The proteins on the surface of the malaria parasite are recognised as foreign by the immune system and therefore if the body can be exposed to malaria surface proteins by immunization before the parasite attacks, the immune system will be primed to destroy the parasite. For such a strategy large quantities of the malaria surface proteins must be produced and there are two ways in which this can be done. ... If the malaria gene which carries the information for the synthesis of the protein we wish to use in the vaccine can be identified, it can be transferred to another type of cell, for example a bacterium, which will then produce large amounts of the protein. ... Identification of the proteins that are recognised by the immune system of people who have had malaria and have therefore developed immunity, can narrow down the search even further.
Although vaccines for viral and bacterial diseases have existed for many years, this is not the case for the malaria parasite or any other parasitic disease of humans.
Approximate Word count = 2772
Approximate Pages = 11.1
(250 words per page double spaced)
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