The World Health Organisation said Tuesday it was optimistic drug-resistant malaria that has emerged along Thailand's borders with Cambodia and Myanmar could be contained within the region.
Malaria that was resistant to the commonly used anti-malarial artemisinin emerged on the Thailand-Cambodia border eight years ago, and has since also been discovered along the Thailand-Myanmar border, scientists say.
"This emerged around eight years ago, and so far we haven't found any artemisinin resistance outside the Mekong region," WHO expert Pascal Ringwald told reporters in Bangkok, noting containment efforts were also in place.
"I think we have good chances to keep it in the Mekong region," he added.
But he also said the drug resistance on the two Thai borders appeared to be "totally independent, and it raises a concern that it could emerge anywhere."
A pair of studies published in The Lancet and the journal Science earlier this month of 3,202 patients along the northwestern border of Thailand near Myanmar from 2001 and 2010 indicated a steady increase in drug resistance.
Resistance to artemisinin does not prevent patients being cured thanks to partner drugs, but treatment typically takes a few days instead of 24 hours, said Ringwald.
Malaria is a life-threatening disease caused by parasites that are transmitted through the bites of infected mosquitoes.
It killed an estimated 655,000 people in 2010, mostly African children, although mortality rates have fallen sharply over the past decades, according to the WHO.