Red alert for antimalarial resistance

Malaria affects 500 million people a year killing over 2 million.Scientists at St George’s, University of London, have shown how the malaria parasite has the potential to become resistant to artemisinins, the most effective drugs for treating this disease, especially highly drug-resistant malaria.Artemisinins work by interfering with a parasite transport protein called PfATP6 and Professor Sanjeev Krishna and his team have shown why they only hit the parasite transporter and not similar transporters in human cells.These findings, published in July’s Nature Structural and Molecular Biology, but available today on line at http://www.nature.com/nsmb/journal/vaop/ncurrent/abs/nsmb947.html, have far reaching implications.

Changing one amino acid can make the parasite transporter (PfATP6) completely resistant to artemisinins. “This is an incredibly worrying observation” says Professor Sanjeev Krishna who leads the team studying how artemisinins work. “The parasite transporter also becomes resistant to artemisone - and artemisone is 5 to 10 times better at killing parasites than any other artemisinin we have.” The research, funded by The Wellcome Trust (UK), highlights how detailed laboratory studies encourage us to monitor parasites whenever artemisinins are used, even before resistance develops. Artemisone was discovered by Professor Richard Haynes, University of Hong Kong.

Krishna comments: “We are really lucky not to have seen resistance to artemisinins in malaria parasites so far. History of other antimalarials tells us that resistance is highly likely to develop when artemisinins are used widely. At least we know one more thing we should now be watching out for in parasites. We also urgently need to find new drugs.”