Resistance among malaria parasites in Africa to a widely used drug is due to 'migration' of resistant parasites from South-East Asia, according to research published in Science today (20 August).
The study, led by Cally Roper of the UK London School of Hygiene and Tropical Medicine, compared the genetic makeup of malaria parasites from South-East Asia and Africa. Its results suggest that parasites resistant to sulfadoxine pyrimethamine (SP) originally arrived in Africa from South-East Asia, where resistance is common.
This finding contrasts with previous assumptions that the African parasites had evolved resistance in response to the use of the drug there.
"Importantly, these data demonstrate that anti-malarial drug resistance is an international problem requiring a coordinated international response," write the researchers.
They suggest that people travelling to Africa from South-East Asia and from Latin America, where SP resistance is also common, should be screened for malaria in order to limit the spread of resistance. However, Allan Shapira of Roll Back Malaria, a World Health Organisation initiative, told BBC Online that this would be an "onerous task".
Roper and colleagues also suggest the problem of SP resistance could be tackled by widespread use of therapies containing artemisinin, a chemical extracted from plant used in traditional Chinese medicine to treat fever.
Artemisinin-based therapies cure 90 per cent of patients within three days and no cases of resistance to the drugs have yet been recorded. For these reasons, the Global Fund to Fight AIDS, Tuberculosis and Malaria recently announced that all future grants for Africa will require use of artemisinin (see Artemisinin is now drug of choice, fund tells Africa).
Today's news follows the announcement yesterday (19 August) that a team of researchers has created a potentially powerful new drug capable of killing the malaria parasite. The synthetic drug mimics artemisinin and would be far cheaper to produce than current treatments if approved for use (see Drug breakthrough in fight against malaria).