In the latest issue of Nature Genetics, scientists traced the genetic patterns of parasite subpopulations that seem to have developed resistance to current first-line antimalaria drugs. The results — derived from samples collected in western Cambodia — identify three distinct strains whose alarming drug resistance may help explain the recent epidemic in South-East Asia.

In addition, the study catalogues the genetic markers that distinguish the resistant strains from other strains. Researchers believe this could prove instrumental in future epidemiological efforts to track the spread and evolution of these resilient subpopulations.

For the last few decades, the go-to antimalaria treatment has been artemisinin — a standard, fast-acting family of drugs, whose active compound originates in Chinese traditional medicine. While the drug's mechanism of action remains somewhat obscure, research usually links the efficacy of artemisinin and its derivatives to a tremendously complex process whereby the treatment's chemical minutia disrupts parasitic business within red blood cells.

Researchers have recently noted the emergence of artemisinin-resistant strains in the epicenter of the South-East Asian epidemic — a development long feared by the World Health Organization (WHO). With cases spreading into neighboring regions, public health is at the risk of being further imperiled. These strains now threaten to corrode national prevention strategies that rely on artemisinin as the cornerstone of its medical program.

The new study comes in response to the dire need of a comprehensive genetic blueprint of these resistant subpopulations. From a large set of cases, scientists have isolated and assessed the genomes of plasmodium falciparum, a parasite known to cause malaria infections in humans. By determining and comparing — or, sequencing — the pathogens' hereditary codes, Dr. Kwiatkowski and his colleagues have been able to identify several unusual and genetically disparate strains.

Within this set, the data indicates three particularly nefarious strains that all exhibit resistance to artemisinin treatment. An additional cause for alarm is the fact that analyses of population structures suggest that the strains have not only spread, but begun to display the "founder effect" — which, in genetics, refers to the process whereby a small, nascent population of organisms gradually loses its internal genetic variation and slowly but steadily begins to form a larger, homogenous population.

Hopefully, these new insights will aid in the tracking and subsequent elimination of these drug resistant strains. The study provides statistical data that can be used by organizations and other research teams to observe the spread and geographical distribution of the various subpopulations. The results will hopefully underpin future projects, and thus prove a valuable tool in the scientific community's efforts to combat one of Africa and Asia's greatest health risks.

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