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[BANGKOK] Researchers have identified new drug-resistant strains of the malaria parasite in western Cambodia — a region where resistance has emerged before — adding to knowledge that could be crucial in tracking the spread of drug resistance.

A study published this week in Nature Genetics reveals three distinct subpopulations of Plasmodium falciparum, the malaria-causing parasite, that are resistant to the current main drug treatment, artemisinin.

"Artemisinin is the first line of defence against malaria. So the spread of the drug-resistant parasite population is an emergency since it threatens all efforts to curb malaria incidence," says Olivo Miotto, lead author and a senior fellow at the Mahidol Oxford Tropical Medicine Research Unit in Bangkok, Thailand.

SPEED READ

  • There are distinct strains of artemisinin-resistant parasites in western Cambodia
  • It is crucial to track artemisinin-resistance to tackle malaria in all areas
  • The region could yield more clues about how resistance emerges
Scientists from 23 institutions in Africa, South-East Asia, the United States and United Kingdom sequenced the genomes of more than 800 P. falciparum samples from Africa and South-East Asia to identify and track drug resistance.

 

Dominic Kwiatkowski, a senior author of the study and a malaria researcher at the Wellcome Trust Sanger Institute, United Kingdom, says western Cambodia has emerged as a hotspot for drug resistance, although the reasons are unclear.

The population structure of the resistant parasites in the region is "strikingly different" to other countries analysed, he notes.

"We found three distinct subpopulations of drug-resistant parasites that differ not only from the susceptible parasites, but also from one another. It is as if there are different ethnic groups of artemisinin-resistant parasites inhabiting the same region," Kwiatkowski said in a statement.

Laurent Renia, principal investigator and malaria specialist at the Singapore Immunology Network, says there is an urgent need to know more "about the biology of these parasites to understand their mechanism of resistance".

He says if artemisinin-resistant malaria spreads to the rest of the world it will be "a real problem — we may see outbreaks and epidemics since we don't have new, efficient antimalarial drugs".

Resistance to other malaria drugs, namely chloroquine and sulfadoxine/pyrimethamine, first developed in South-East Asia before spreading to Africa. This is why, Miotto adds, this research will benefit not only South-East Asia but also Africa and other countries where malaria remains a problem.

"Our findings are not only relevant to South-East Asia as the importance of preserving the effectiveness of artemisinin will also be felt in other regions," he says.

Earlier this year, scientists published research on genetic markers for an artemisinin-resistant malaria strain found in the Mekong region of South-East Asia.
 

This article has been produced by SciDev.Net's South-East Asia & Pacific desk.

Link to full paper in Nature Genetics

References

Nature Genetics doi:10.1038/ng.2624 (2013)

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