The WHO said that “the emergence of parasites resistant to artemisinin at the Thai-Cambodia border could seriously undermine the success of the global malaria control efforts.” WHO noted that surveillance systems and research studies it supports to monitor antimalarial drug efficacy “are providing new evidence that parasites resistant to artemisinin have emerged along the border between Cambodia and Thailand.”

Strong malaria control programmes have helped to lower infection rates in several countries, WHO said, and the recent shift from failing drugs to the highly effective artemisinin-based combination therapies (ACTs) has been a breakthrough. Appropriate treatment with ACTs succeeds in more than 90% of cases. But malaria drug resistance now emerging along the Thai-Cambodia border threatens these gains.    Resistance along the Thai-Cambodia border started with chloroquine, followed by resistance to sulfadoxine-pyrimethamine and mefloquine, drugs used in malaria control several years ago.

With a US$ 22.5 million grant from the Bill & Melinda Gates Foundation, WHO said it “will endeavour to contain artemisinin-resistant malaria parasites before they spread.” WHO will work in collaboration with several key partners including the National Center for Parasitology, Entomology and Malaria Control of the Cambodian Ministry of Health, Bureau of Vector-Borne Disease of the Thai Ministry of Public Health, Faculty of Tropical Medicine of Mahidol University Bangkok, Institut Pasteur Cambodia, Mahidol Oxford Tropical Medicine Research Unit, Bangkok and the Malaria Consortium.

http://www.who.int/mediacentre/news/releases/2009/malaria_drug_resistance_20090225/en/index.html