Bangkok--Drug-resistant malaria superbugs threaten a global public health disaster unless urgent action is taken to fight their spread in Southeast Asia, authors of new research have warned.
The mosquito-borne uber-parasites have taken hold in parts of Thailand, Laos and Cambodia and could sweep into India and on to Africa where most malaria deaths occur, their results suggest.
The conclusions will deepen concerns that growing resistance to the main artemisinin class of antimalarial drugs might reverse international success in almost halving estimated death rates from the disease over the past 15 years.
Sir Nicholas White, co-author of the research published on Thursday in The Lancet Infectious Diseases, warned that the last wave of drug-resistant malaria parasites to spread from Asia to Africa “killed millions”.
“History is repeating itself,” said Sir Nicholas, a professor at Oxford University and Bangkok’s Mahidol University. “The consequences of resistance spreading further into India and Africa could be grave if drug resistance is not tackled from a global public health emergency perspective.”
Parasites that cause the deadly falciparum strain of malaria are showing resistance in parts of Southeast Asia both to artemisinin and its widely used partner drug piperaquine, the research found. Multi-drug resistant bugs are spreading throughout western Cambodia, southern Laos and northeastern Thailand, the scientists said.
Researchers and health professionals fear hard-to-monitor areas such as rural southern Myanmar could host further pockets of resistance to artemisinin, an extract from the sweet wormwood plant that has been used against malaria for centuries in Chinese traditional medicine. Myanmar is crucial because it borders India, which could be a gateway for the further global spread of drug resistance.
Artemisinin has been a critical part of an international antimalarial effort the World Health Organization estimates led to deaths from the disease falling from 839,000 in 2000 to 438,000 in 2015. If artemisinin loses its effectiveness, there is no widely accepted immediate replacement--unlike during previous outbreaks of drug resistance.
Several separate cases of malaria drug resistance were reported last month in the UK, in patients who appeared to have contracted the disease in countries spread across Africa--Uganda, Angola and Liberia. The sufferers all recovered initially after being given artemisinin-based treatments in late 2015 and early 2016 but returned within six weeks with recurrent symptoms and increased parasite numbers in their blood.
The London School of Hygiene & Tropical Medicine, which investigated the cases, said it had found new strains of the falciparum parasite showing “a potential first sign of drug resistance”. None of the patients seemed to have contracted the disease in the Asian countries covered by the Lancet Infectious Diseases study.
Colin Sutherland, reader in parasitology at the London School of Hygiene, said: “These cases act as a warning for Africa. Drug resistance is one of the biggest threats we face in fighting malaria, and is already starting to occur in parasite strains prevalent in parts of Southeast Asia.”