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Malaria has killed more people than all wars throughout human history combined. Thanks to eradication efforts, it is far less common than it once was. But every year malaria still kills a quarter of a million children, the most vulnerable group, in Africa alone. But again and again, the disease has become resistant to the treatments used to defeat it. Malaria cases start in humans with a bite from certain kinds of Anopheles gambiae mosquito. During the bite, malaria parasites are injected into the bloodstream and travel to the liver. In this next stage, they multiply and rupture liver cells.
Then they infect red blood cells destroying them. Anti-malarial drugs work by attacking the malaria parasite in the blood cells. But the malaria parasite has adapted time and again. It has formed resistance to some of the most powerful anti-malarial drugs from chloroquine to mefloquine. Malaria's ability to resist drugs is one of the reasons success in eradicating it has leveled off. New ways to tackle malaria are being developed seeking to wipe out the mosquitoes that carry the disease. A gene-editing technology called CRISPR is being used to engineer a "gene drive". This creates selfish genes that are always passed onto offspring. The aim is to interfere with fertility by driving a gene for sterility through an entire population. As it is passed from generation to generation, the population would be swamped with insects that are unable to reproduce. In theory, they could be driven to extinction. Last year a team at Imperial College London successfully created a gene drive that wiped out enclosed cohorts of one species of malaria-carrying mosquito. But there is no guarantee that gene drives could work in the many environments where malaria is found in the world especially in Africa. Humanity has shown that it can control malaria. It has been eradicated in around 35 countries. Currently, the best hope lies in a combination of methods. But in the future, a gene drive may be the most effective solution.
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