Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Multidrug-Resistant Malaria Spreading in Southeast Asia, Study Shows Reuters LONDON - Strains of malaria resistant to two key anti-malarial medicines are becoming more dominant in Vietnam, Laos and northern Thailand after spreading rapidly from Cambodia, scientists warned Monday. Using genomic surveillance to track the spread of drug-resistant malaria, the scientists found that the strain, known as KEL1/PLA1, has also evolved and picked up new genetic mutations which may make it yet more resistant to drugs. "We discovered [it] had spread aggressively, replacing local malaria parasites, and had become the dominant strain in Vietnam, Laos and northeastern Thailand," said Roberto Amato, who worked with a team from Britain's Wellcome Sanger Institute and Oxford University and Thailand's Mahidol University. Malaria is caused by Plasmodium parasites which are carried by mosquitoes and spread through their blood-sucking bites.