A new drug-resistant malaria strain found near the Cambodian and Thai border was threatening global efforts to control and eradicate the disease, the World Health Organisation (WHO) said on Friday.
In many parts of the world, malaria deaths have been declining, particularly in Zambia where fatalities have fallen by two-thirds since 2000, the WHO said.
But the campaign to eradicate the disease is at risk from a new strain of drug-resistant malaria first detected in 2007 in the Mekong area, Shin Young-soo, regional director of WHO Western Pacific area, said in a statement on Friday.
"We have to act now to contain this problem within the Mekong region. It must not be allowed to spread and become a regional and international threat," Shin said.
Latest clinical tests on about 20-50 people infected with the new strain and treated with artemisinin, the most effective drug available to fight the disease, confirmed that it was becoming resistant, said the WHO's Eva Christophel, a malaria expert.
"We have obtained scientific evidence that this is very unusual," Christophel told Reuters. "This is really worrying."
In most malaria cases, people are freed of the parasite in their blood after only three days of artemisinin intake, said Christophel. But for people who were infected with the new strain, the reaction to the drug was much slower. (Reporting by Manny Mogato; Editing by Rosemarie Francisco)