A 10-year study has found a malaria strain increasingly resistant to the most effective drug used to treat the disease, has spread along the Thai-Myanmar border.
The study, published in The Lancet medical journal, says the strain may reach India and Africa unless ways are found to contain it, Reuters reports.
Researchers observed that patients at malaria clinics took longer to get better when treated with combination therapies containing artemisinin - a drug derived from the sweet wormwood shrub.
It is recognised as the best drug against malaria and the spread of the drug-resistant strain has been blamed on incorrect use of artemisinin and fake and substandard versions of the drug.
Malaria killed an estimated 655,000 people in 2010.