The current spread of multidrug-resistant malaria in southeast Asia is likely to be the result of two mutations combining in 2008, according to a retrospective genetic study published in The Lancet Infectious Diseases journal. The study shows how the multidrug-resistant parasite gained increased biological fitness, spreading rapidly through the region unnoticed for 5 years until the outbreak became apparent in 2013. The authors warn that malaria programmes should closely monitor genetic mutations to mitigate the possibility of the parasite becoming untreatable.

Roberto Amato from Wellcome Sanger Institute, UK says, "While it would be catastrophic if resistance developed in the same way for the last remaining anti-malarial drugs, it is now possible to conduct genetic surveillance of malaria cases, allowing researchers to respond as soon as possible to changes in the parasite population. It is important that we embrace these technologies so that major outbreaks of resistance do not go unnoticed in the future, and to reduce the risk of a global health emergency."