The parasite that causes the deadliest form of malaria is showing the first signs of resistance to the best new drug against it, the New York Times reported on January 26, citing recent medical studies and interviews with medical experts including Dr. John MacArthur of the U.S. Agency for International Development.

Dr. MacArthur raised concern last April, on World Malaria Day, noting that scientific evidence is emerging that malaria parasites from Cambodia’s border with Thailand are increasingly tolerant to artemisinin-based combination therapy (ACT), one of the most effective therapies against multi-drug resistant malaria.

“There are currently few alternatives to ACTs available for the treatment of the deadly falciparum malaria,” said Dr. MacArthur, the infectious diseases advisor at USAID’s Regional Development Mission for Asia. “It is imperative that the region act now to contain the spread of this parasite.”

The article, which also appeared in the International Herald Tribune, noted that a series of new studies “have cemented a consensus among researchers that artemisinin is losing its potency here (in Cambodia) and that increased efforts are needed to prevent the drug-resistant malaria from leaving here and spreading across the globe.”

It stated there are no new drugs to take the place of artemisinin-based combinations and no immediate prospects under development.

”While the number of malaria cases in Thailand and the GMS is low in comparison with Africa, the parasites in this region are among the world’s most dangerous due to their resistance to most of the commonly used malaria medications,” Dr. MacArthur said.

“Countries in the region can continue their successful efforts against malaria by acting now to monitor for drug-resistant parasites,” Dr. MacArthur added. “When found, they must act decisively to contain those parasites from spreading,” he said, noting there have been advances against the disease worldwide.

Recognizing the global threat of ACT resistance, USAID is working with the World Health Organization and national malaria control programs throughout the Greater Mekong Subregion (GMS) to strengthen surveillance for anti-malarial drug resistance, improve laboratory diagnosis, and ensure that patients are treated with high-quality anti-malarial drugs. Clinical workers are being taught to properly use laboratory test results when prescribing treatments and to support efforts to eliminate counterfeit anti-malarial drugs.