Scientists have identified new drug-resistant strains of the parasite that causes malaria.
A study by an international team of researchers says that gene analysis of malaria parasites has pinpointed western Cambodia as the hotspot of the new strains.
The study, published in the journal "Nature Genetics," says the strains are dangerously resistant to artesiminin, the front-line drug against the mosquito-borne disease.
Scientists sequenced the genomes of more than 800 samples of the malaria-causing parasite Plasmodium falciparum collected from around the world.
The 166 samples from western Cambodia stood out, with three distinct groups of drug-resistant parasites whose genetic mutations made them resistant to artesiminin.
The UN's World Health Organization says malaria causes around 650,000 deaths each year, mostly African children under five.
Based on reporting by AFP and BBC