“Artemisinin combination treatments, or ACTs, are the first-line drugs for treating malaria recommended by the WHO, and the most important weapon in fighting against malaria worldwide,” Tu was quoted as saying.

“If plasmodia [the parasite which causes malaria] generally become drug resistant, the consequences will be severe. Scientists around the world are all very worried about drug resistance to artemisinin getting worse,” she said.

The 88-year-old scientist and her team proposed two steps to solve the problem – extending the course of treatment from three to five or seven days, and finding alternatives to the supplementary synthetic drugs used in ACTs. Their research was published in the New England Journal of Medicine last month.

Speaking on Friday, Tu said the two steps could mean artemisinin “will still be highly effective and the drug of first choice in fighting malaria”. She said that was important because the drug was cheap – costing just a few dollars for a course of treatment.

“It’s suitable for poor regions in Africa where there is a high incidence of epidemics and that means it can help to achieve the global goal of eliminating malaria completely,” Tu said.

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Pedro Alonso, director of the WHO’s Global Malaria Programme in Geneva, said the work of Tu and her team had been “groundbreaking”.

“Global malaria control is in line with the thrust of the Chinese government’s initiative to build a community with a shared future for humanity,” Alonso was quoted by Xinhua as saying.

“The antimalarial research work carried out by Tu Youyou’s team is groundbreaking, outstanding and immeasurable.”

Malaria is a life-threatening disease that is caused by parasites and transmitted through mosquito bites. There were an estimated 219 million cases of malaria worldwide in 2017, according to the WHO.

About 435,000 people died of the disease that year, 61 per cent of whom were children under the age of five. The WHO estimates that a child dies from the preventable and curable disease somewhere in the world every two minutes.

Wang Jigang, a member of Tu’s team and a researcher at the China Academy of Chinese Medical Sciences, said they decided to try prolonging the treatment period after discovering that artemisinin was only effective in killing plasmodia for a total of a few hours over a three-day course.

“Artemisinin-resistant strains have taken advantage of this and either altered their life cycle or stayed dormant to avoid being killed [by the drug],” Wang told the news agency.

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But malaria expert Tang Linhua said it was “a step forward” rather than a breakthrough.

Tang, a senior member of China’s malaria elimination committee backed by the National Health Commission, said drug resistance to artemisinin was a key research area for scientists around the world, but so far there had been no substantial progress.

“My team has researched this issue in an area of Yunnan province that borders Laos and Myanmar over the past decade and our conclusion was similar to that of Tu and her team,” Tang said.

“I think Tu Youyou’s recent discovery is a step forward in our efforts to understand drug resistance. But there are still many unknowns, such as through which channels – protein or gene – drug resistance evolves.”

He said patients were likely to develop resistance from taking excessive and irregular doses of the medicine. “We know that some people, although they are not suffering from malaria, have taken artemisinin as a preventive treatment,” Tang said.

Tu, a traditional Chinese medicine specialist, joined a state-backed research project in the late 1960s to search for an antimalarial drug, which involved testing more than 200 herbal medicines. Artemisinin is derived from sweet wormwood, a plant that has been used for more than 2,000 years in China to treat infectious diseases.