April 27th, 2012 by James Ayre
New mutations in the deadliest malaria parasite have given it resistance to the most powerful antimalarial drugs available. The researchers that did the study say that this should serve as a warning, that the best weapons against malaria may become ineffective.
The parasite has developed resistance to artemether, one of the two most effective of the artemisinin group of drugs. They are the most effective and widely used drugs to combat malaria.
The study was done by a team at the University of London. They discovered artemether resistance in 11 out of 28 parasite samples, taken from patients who got it traveling abroad, mostly in sub-Saharan Africa. 90 percent of the one million deaths that are caused by malaria every year, are in sub-Saharan Africa.
“Artemether and ACTs are still very effective, but this study confirms our fears of how the parasite is mutating to develop resistance. Drug resistance could eventually become a devastating problem in Africa, and not just in south east Asia where most of the world is watching for resistance. Effective alternative treatments are currently unaffordable for most suffering from malaria. Finding new drugs is, therefore, crucial,” lead researcher Sanjeev Krishna is quoted as saying.
All 11 resistant parasites contained the same mutation, but the resistance was strongest in the parasites that also contained another separate mutation.
Professor Krishna says: “At the moment, we do not know if the other artemisinins will follow suit, but given the shared chemistry they have with artemether it is tempting to think that they would.”
He also said that the resistance could be caused by the increased use of the drug — 300 million doses were used worldwide in 2011. Greater use gives more opportunity for advantageous mutation. This will lead to a repeat of the resistance that malaria developed to chloroquine.
“New drug development is paramount, but it is vital that we also learn more about how artemisinins work so we can tailor ACT treatments to be effective for as long as possible,” Profesor Krishna says.
Malaria is predicted to spread far outside of its current range as climate change progresses, enabled by the increasing heat and precipitation.
Without effective treatment it will affect far more people than it currently does.
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