An attending physician in a Congo clinic has successfully cured 18 patients with drug-resistant malaria using a drug that was made entirely from the dried leaves of the sweet wormwood (Artemisia annua) plant.

The drug, described in a paper published in the journal Phytomedicine, is a not-yet-approved malaria therapy pioneered by Pamela Weathers, Ph.D., a professor of biology and biotechnology at the Worcester Polytechnic Institute (WPI). Doctors at the clinic prescribed the sweet wormwood drug after all standard malaria treatment failed to cure the patients.

"These 18 patients were dying," said Weathers in a press release. "So to see 100 percent recover, even the child who had lapsed into a coma, was just amazing. It's a small study, but the results are powerful."

At first, the patients were treated with artemisinin-based combination therapy (ACT), which is the recommended medication for malaria. ACT is the combination of artemisinin and one or more drugs that attack malaria parasite in different ways. Artemisinin is a chemical extracted from the Artemisia annua plant.

The patients did not respond to the standard ACT treatment and lapsed into severe malaria. A five-year-old patient even went into coma. They were treated with intravenously administered artesunuate, which is considered to be the frontline medication against severe malaria. Symptoms of severe malaria may include convulsions, respiratory distress, loss of consciousness and pulmonary edema. Once again, the patients did not show any signs of improvement.

Without seeing any improvement in the patients, the doctors acted under the "compassionate use" doctrine and prescribed tablets made from dried and powdered leaves of the sweet wormwood plant. After five days of treatment, all the patients fully recovered. Laboratory tests showed that there no malaria parasites remained in their blood.

The sweet wormwood tablets used by the doctors in Congo were prepared and analyzed using methods develop by Weathers and postdoctoral fellow Melissa Towler. Weathers noted that the drugs made from dried sweet wormwood leaves have already cured over 100 drug-resistant patients.

Malaria is caused by a mosquito-borne parasite that has been reported in nearly 100 countries and threatens almost half of the world's population. In 2015, over 212 million contacted malaria, including 429,000 that died.