New Genome Sequencing Technologies Detect Populations of Malaria-Resistant Parasites

Resistance to artemisinin and its derivatives is well established in western Cambodia and is spreading across South East Asia. In response to this concerning situation an international collaboration surveyed the genomes of parasite populations from regions of emerging artemisinin resistance. The scientists revealed this week that they have found unusual genetic properties that may be useful to identify parasites that carry the resistance traits. 

Focused on local parasite populations in western Cambodia the research outlines how the latest genome sequencing technologies are revealing multiple sub-populations of drug resistant parasites (Plasmodium falciparum) within the same geographic area. Professor Dominic Kwiatkowski, senior author of the paper from the Wellcome Trust Sanger Institute and University of Oxford, confirms, “Initially, we thought our findings might be just an anomaly. But when we investigated further we found three distinct sub-populations 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.”

Sequencing of parasite genomes was performed from 825 malaria samples from 10 locations in West Africa and from South East Asia. The large-scale analysis revealed a marked difference in the population structure of parasites from western Cambodia compared to other countries analysed including eastern regions of Cambodia, neighbouring Thailand and Vietnam, and much further afield in Africa. It is anticipated that these genomic differences may offer new leads as to why drug resistance emerges and is more prevalent in some regions of South East Asia and not in others. This work will add to the efforts of researchers examining the genetic differences to define simple markers of artemisinin response, and molecular mechanisms of artemisinin resistance. 

Researchers still need to identify the exact genetic causes of artemisinin resistance; however, these innovative approaches are enabling the quick identification of resistant strains from the Mekong region – an important step in the collaborative effort to identify molecular markers to support effective worldwide surveillance. The characterisation of distinct genetic patterns or ‘fingerprints’ for each of the strains in real time can provide us with a more complete and up-to-date profile of parasite resistance in critical areas. 

Dr. Olivo Miotto, from Oxford University, Mahidol University in Thailand, and the MRC Centre for Genomics and Global Health, confirms an urgent need to develop this genomic approach, “Public health authorities need rapid and efficient ways to genetically detect drug-resistant parasites in order to track their emergence and spread.” 

News of this significant release came from the Wellcome Trust Sanger Institute, one of the world's leading genome centres and WWARN partners. 

View the full publication on the Nature Genetics website. Miotto O, Almagro-Garcia J, Manske M et al. Multiple populations of artemisinin-resistant Plasmodium falciparum in Cambodia. Nature Genetics 2013.