#Resistance Taking Sting Out of Top #Malaria Drug - WSJ
Resistance to the world’s most effective drug against malaria is becoming widespread in Southeast Asia, a recurrent pattern that threatens global efforts to control the mosquito-borne infectious disease, a new study shows.
Resistance to the drug, #artemisinin, in the most deadly form of malaria-causing parasite, #Plasmodium falciparum, is established in northern and western Cambodia, Thailand, Vietnam and eastern Myanmar, according to the study published Thursday in the New England Journal of Medicine.
The research, coordinated by the Mahidol Oxford Tropical Medicine Research Unit in Bangkok, analyzed blood samples from 1,241 malaria patients in 10 Asian and African countries between 2011 and 2013.
Fear is growing that resistance would spread from Asia to Africa—where progress has been made in reducing deaths from malaria—in a way that neutered previous treatments. So far, three African sites included in the study—in Kenya, Nigeria and Congo—showed no signs of resistance.
This is the third time that the malaria parasite has developed resistance to drugs. Each time previously it emerged from the Cambodian-Thailand border and spread to other countries, including in Africa.
Resistance to chloroquine spread from the late 1950s into the 1970s, resulting in a resurgence of malaria infections and millions of deaths. Then, sulphadoxine-pyrimethamine was introduced before a resistance emerged. It was replaced by artemisinin combination therapies.
Resistance to artemisinin has been driven by the misuse of the drug eroding its efficacy. It takes six days of treatment to clear parasites in patients on the Thai-Cambodian border instead of the standard three, the study found.
Researchers found that patients whose infections were slow to clear were also more likely to transmit their drug-resistant strain to others.
Mr. White urged more radical action, such as targeted malaria elimination, to prevent the spread of resistance. The approach would require officials to identify people who are healthy but carry malarial parasites, especially on western border of Myanmar.
“The artemisinin drugs are arguably the best antimalarials we have ever had. We need to conserve them in areas where they are still working well,” said Elizabeth Ashley, the lead scientist of the study.
New antimalarial medicines are being developed and have shown some promise, but are unlikely to be available for distribution for several years, another paper published in the New England Journal of Medicine showed.