Drug-Resistant Malaria in Asia May Remain Contained, WHO Says

The World Health Organization expects a drug-resistant malaria strain in Southeast Asia can be contained amid signs it may have emerged in Vietnam.

“We have good chances to keep it in the region,” Pascal Ringwald, coordinator of the WHO’s drug resistance and containment unit, told reporters in Bangkok today. “We need more information but on the other hand, I haven’t the impression it’s spreading very quickly.”

Studies in Cambodia and Myanmar have shown that artemisinin-based malaria drugs are losing potency in Southeast Asia. The WHO is conducting studies to confirm possible strains in Myanmar and Vietnam, he said, adding that containment efforts begin once resistance is suspected.

“To confirm artemisinin resistance you need to go to very sophisticated research studies,” Ringwald said. “It’s extremely complicated.”

Malaria strikes about 216 million people each year and kills about 655,000, mostly children under five in Africa, according to the Geneva-based WHO. Resistance can emerge independently in any part of the world, Ringwald said.

The disease is caused by a tiny parasite called Plasmodium that’s carried in the saliva of female mosquitoes. Artemisinin-based drugs clear most of the parasites within hours. Their main drawback is they don’t last long in the body, so are usually paired with another less powerful but longer-acting drug that mops up the stragglers.

The use of artemisinin-based drugs without their companion pills has contributed to the emergence of the resistant strain because it clears all but the hardiest parasites. Counterfeit medicines, which contain insufficient quantities of artemisinin, may have also contributed to the resistance, the WHO said.

Artemisinin has been used in Southeast Asia more than anywhere else in the world, Ringwald said. “Massive” use may have contributed to the development of resistance, he said.

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