Multidrug-resistant malaria superbugs have taken hold in parts of Thailand, Laos and Cambodia, threatening to undermine progress against the disease, scientists said.

The superbugs — malaria parasites that can beat off the best current treatments, artemisinin and piperaquine — have spread throughout Cambodia, with even fitter multidrug resistant parasites spreading in southern Laos and northeastern Thailand.

"We are losing a dangerous race to eliminate artemisinin-resistant ... malaria before widespread resistance to the partner antimalarials makes that impossible," said Nicholas White, a professor at Oxford University in Britain and Mahidol University in Thailand who co-led the research.