Malaria is a serious tropical disease, caused by a parasite, and spread by mosquitoes. If malaria is not diagnosed and treated promptly, it can be fatal. Through scanning the genomes of malaria parasites (Plasmodium falciparum) collected from 15 locations in Southeast Asia, scientists based at the Wellcome Trust Sanger Institute have identified bio-markers of resistance in relation to the frontline antimalarial drug artemisinin.
Artemisinin is an antimalarial lactone derived from qing hao (or sweet wormwood). The medicinal value of this plant has been known to the Chinese for at least 2,000 years. It was taken up by drug companies in the battle against malaria.
For a number of years the drug proved to be an effective treatment. However, parasite resistance to artemisinin has so far been detected in five South-East Asian countries: in Cambodia, the Lao People’s Democratic Republic, Myanmar, Thailand and Viet Nam (all in the Greater Mekong subregion). For these reasons, scientists are keen to understand what is at play in terms of resistance.
By undertaking a human genome-wide association study, the researchers homed in on around 20 mutations in a gene called kelch13. The genes are associated with slow parasite clearance rate after treatment with artemisinin-related compounds. Overall, the researchers found evidence to suggest that “the risk of new resistance-causing mutations emerging is determined by specific predisposing genetic factors in the underlying parasite population” (as quoted in the research paper.)
Olivo Miotto of the Mahidol-Oxford Tropical Research Unit in Thailand, commenting on the study, told BBC News: “Artemisinin is the best drug we have had for a very long time, and we want to continue this success story…And for that, its effectiveness has to be protected and sustained.”
The findings have been published in the journal Nature Genetics. The paper is titled “Genetic architecture of artemisinin-resistant Plasmodium falciparum.”
