Malaria resistant to key drug is found in Africa

Scientists say finding is big worry for African nations.

Scientists have found evidence of a resistant form of malaria in Uganda, a worrying sign that the top drug used against the parasitic disease could ultimately be rendered useless without more action to stop its spread.

Researchers in Uganda analyzed blood samples from patients treated with artemisinin, the primary medicine used for malaria in Africa in combination with other drugs. They found that by 2019, nearly 20% of the samples had genetic mutations suggesting the treatment was ineffective. Lab tests showed it took much longer for those patients to get rid of the parasites that cause malaria.

Drug-resistant forms of malaria were previously detected in Asia, and health officials have been nervously watching for any signs in Africa, which accounts for more than 90% of the world’s malaria cases. Some isolated drug-resistant strains of malaria have previously been seen in Rwanda.

“Our findings suggest a potential risk of cross-border spread across Africa,” the researchers wrote in the New England Journal of Medicine, which published the study Wednesday.

The drug-resistant strains emerged in Uganda rather than being imported from elsewhere, they reported. They examined 240 blood samples over three years.

Malaria is spread by mosquito bites and kills more than 400,000 people every year, mostly children younger than 5 and pregnant women.

Dr. Philip Rosenthal, a professor of medicine at the University of California, San Francisco, said that the new findings in Uganda, after past results in Rwanda, “prove that resistance really now has a foothold in Africa.”

Rosenthal, who was not involved in the new study, said it was likely there was undetected drug resistance elsewhere on the continent. He said drug-resistant versions of malaria emerged in Cambodia years ago and have now spread across Asia. He predicted a similar path for the disease in Africa.

Dr. Nicholas White, a professor of tropical medicine at Mahidol University in Bangkok, described the new paper’s conclusions about emerging malaria resistance as “unequivocal.” “We basically rely on one drug for malaria, and now it’s been hobbled,” said White.