The results of a two-year study have found that the parasite plasmodium falciparum, which first emerged in Cambodia in 2008 and is resistant to the most potent antimalarial drugs, remains confined to Southeast Asia and has not spread to Sub-Saharan Africa.

The new findings were revealed in the New England Journal of Medicine on Wednesday, which said the revelations were made after the first global mapping of resistance to artemisinin, currently the primary drug used to treat the parasite.

An international consortium supported by the World Health Organization conducted research in 59 malaria endemic countries over the past two years.

“We now have the tools to monitor anti-malaria resistance,” said one of the lead researchers, Dr Didier Menard of the Malaria Molecular Epidemiology Unit at the Pasteur Institute in Cambodia. “The next step is to find a combination of drugs to treat it differently.”

The study follows up on a 2014 discovery by researchers in Cambodia and Paris, who identified a gene, referred to as K13, as the major determinant of artemisinin resistance to plasmodium falciparum.

“No evidence of artemisinin resistance was found outside Southeast Asia and China, where the resistance-associated K13 mutations were confined,” the study reads.

“Widespread artemisinin resistance would have dramatic consequences, since replacement of therapies are limited and threatened by resistance.”

The research found that the most common mutation found in Africa was not associated with resistance, Menard said.

The WHO has estimated that there were 214 million cases of malaria and 438,000 deaths in 2015, most of them in Africa.