A strain identified last year that is known to be resistant to the strongest anti-malarial drug, artemisinin, has been found on the border between Thailand and Myanmar.

A study published in the journal Nature Genetics identified the exact strain of malaria that is resistant to the last line of defense drug. Collaborative teams from the UK found that there were three distinct malaria-causing parasites in the Cambodia area, but did not know how the mutations have made the parasites drug resistant.

Only recently has the last line of defense drug, artemisinin, been able to be mass produced. The drug was traditionally only made from a plant extract and now, with an industrial factory up and running in Italy, close to 25 percent of the malaria treatments will use the drug.

"All the most effective drugs that we have had in the last few decades have been one by one rendered useless by the remarkable ability of this parasite to mutate and develop resistance," Dr Olivo Miotto lead author of the study told the BBC.

"Artemisinin right now works very well. It is the best weapon we have against the disease, and we need to keep it."

What is most disturbing is that the parasite population seen in Southeast Asia has not been seen anywhere in the world and seemed to have developed in isolation.

In western Cambodia, where the resistant parasite originated, 42 percent of all malaria cases involved resistant strains between 2007 and 2010, showing that the Thailand-Myanmar region was swiftly catching up to Cambodia's resistant rates.

Using genetic testing of the parasites, researchers may one day find which genes are directly responsible for developing drug resistance.

The study published in the journal Nature Genetics can be found here.