Drug-resistant malaria parasites have spread to border regions of Southeast Asia, seriously threatening global efforts to control and eliminate the mosquito-borne disease, researchers say. The scientists, who analysed blood samples from 1241 malaria patients in 10 countries across Asia and Africa, found resistance to the world's most effective antimalarial drug, artemisinin, is now widespread in Southeast Asia. However, the study found no signs yet of resistance in the three African sites it covered in Kenya, Nigeria and Democratic Republic of the Congo. It may still be possible to prevent the spread of artemisinin-resistant malaria...