Why Is The Malaria Article So Hard To Solve
pre U Biology essay
Date : 21/06/2017
Malarial infection of human hosts is only likely to be solved by genetic engineering of the human genome or immune system. As such the therapy is likely to throw up many social, economic and perhaps moral issues.
The problem with current therapies is their ineffectiveness. Chemical therapy has been used for thousands of years, Europeans first discovered Peruvian tribes using Quinine extracted from the Cinchona tree and brought the therapy back in the 1600’s.
A similar, synthetic, compound Chloroquine was discovered in 1934 and both are still important treatments. However they do have potent side effects which require careful prescri ption by a physician and severe enough to discourage patients’ compliance with the therapy. The hope is that a better understanding of Plasmodium biochemistry may one day reveal a point of attack for a new drug which would have no side effects and the freely available genome sequence of the parasite will go some great way to helping scientists to achieve this aim. However there is no guarantee that the parasite would not develop resistance to that drug as well as most of the current treatments. Furthermore you would need to take the medication for your entire life, if you were living in an endemic area.
Cheap, effective vaccination would be the ideal solution and there is much research in this direction. However the parasite’s life cycle makes it difficult for a vaccine to work, because within 30 minutes of infection the organism is hidden away inside liver cells which they have invaded and within which they will safely grow. For this reason alone, vaccination is unlikely to ever work by itself, not with the way the human mechanism currently works.
The principle of prevention being better than cure also cannot be successfully applied to Malaria. The only tactics feasible are eradication of the Mosquito or preventing it from biting humans. There are many, many approaches none of which is effective alone. Mosquito nets sprayed with insecticide are currently considered the best in terms of ease of use and cheapness but it only takes one mosquito to get under the net, which is a frustrating weakness to them. Eradication of the mosquito should be considered impossible in monsoon areas because the mosquito larvae can breed in their thousands within a matter of days in any stagnant pool of water. The use of goldfish as natural predators and drainage of swamps is effective in controlling the numbers of mosquitoes.
Interference with the natural life cycle by introducing sterile males is a possibility but the strategy would have to be introduced on a monumentous, global scale and is impractical. Spraying of malarial areas with insecticides, particularly since 1939 with DDT, is certainly feasible and is used effectively indoors, where the insecticide impregnates the walls and kills the insect on contact. However in farmland and swamp areas DDT leaches into waterways and due to bioaccumulation causes infertility and death of the top level carnivores. For this reason DDT is banned from being used in this modality, although its cheapness means it is still used in countries where affordability is a high priority.
The frustrating lack of conclusive victory in the ongoing battle with Malaria has provoked angry reactions in some quarters. Major drug manufacturers have been accused of being uninterested in the disease as there is no interest or economic incentive to do so. Considering Mefloquine was rapidly developed specifically for American troops in the Vietnam war, there is perhaps some truth to this statement. However the fact is that as the human population continues to expand and search for mineral and other resources, they will be forced in ever larger numbers into Malarial regions. Environmentalists can point out that this is a good thing.
The Plasmodium parasite is 100’s of millions of years older than humans. It only infects us (as well as all the vertebrate classes and some invertebrate classes) purely by the chance fact that we appeared on Earth. It can well be considered a guiding force of human evolution, for not only has it resulted in the emergence of Sickle cell disease – which confers immunity – but likely forced many of our ancestors out of Africa and eventually into more temperate climates. Therefore our ancestors were forced to develop the technologies to settle, farm, clothe and defend themselves. In the modern, technological era it is not contraception and family planning which is keeping explosive population growth in check but disease. According to the WHO data for 2006, Malaria alone kills over 1 million people a year and infects just under 250 million.
This now leaves us with the conclusion that we cannot live with Malaria because our modern lifestyles cannot allow us to live in harmony with the environment. As we are unlikely to halt the juggernaut of technological and economic progress, the only likely outcome is that humans will have to modify their own immune systems in ways never done before. This would likely mean gene therapies which would make our immune systems super effective at attacking and destroying the parasite within seconds of its entry. Other possibilities would be altering our genomes so that the parasite would find it impossible to inhabit, invade or reproduce within either hepatocytes or erythrocytes.
Would such a solution be considered too radical? Many scientists would probably argue that the human immune system is currently evolving to do just that and we would only be using technology to speed up the process by many millions of years. However there would likely be many more people who would argue that tampering with the human genome in this way is dangerous not only because of unknown consequences upon the individual but also because of the lingering spectre of eugenics through the back door.
Nevertheless, with current technology it is the only single solution which is likely to be easy to deploy economically and effectively. It is also very difficult to see how the WHO, (which advises governments on malaria) would currently advocate such a technique.
So for now at least, unless there is a breakthrough in chemical therapies, there is unlikely to ever be the eradication of Malaria in our lifetime.
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