New Genetic Mutation Cluster Tied to Drug-Resistant Malaria Spreading Fast in Uganda

Malaria parasites in Uganda are picking up a genetic mutation cluster at a pace researchers call alarming, and it's making the frontline drug used across sub-Saharan Africa and the United States less effective.

A team led by Brown University's Dr. Jeffrey Bailey sequenced the whole genomes of 157 malaria parasite samples pulled from blood collected in Uganda between 2016 and 2024. The findings were published this week in Nature Medicine.

The researchers found a set of mutations in a previously overlooked gene called px1: three amino acid changes plus two deletions. They named the combination PIN. Parasites carrying PIN showed reduced sensitivity to lumefantrine, a key component of artemether-lumefantrine, the most widely used malaria treatment in sub-Saharan Africa, according to Brown University's own press release on the study.

How fast it's spreading

Researchers traced PIN back to a 2008 sample, the earliest confirmed instance, according to Wired's coverage of the study. By 2016, half the samples from northern Uganda already carried it. As of 2024, prevalence hit 84% in northern Uganda and 55% in eastern Uganda.

Normally, genetic recombination breaks up mutation clusters generation after generation. That the PIN mutation is still traveling largely intact through parasite lineages tells researchers it emerged recently and is spreading hard, not gradually drifting through the population.

"It's very concerning that these new mutations are spreading so rapidly. It tells us they are important to the parasite's survival," Bailey said, according to Brown University. "Malaria still is a major killer, particularly in sub-Saharan Africa. As drug resistance continues to emerge, we worry it will undermine control of its spread and result in even more deaths for a large number of people there and beyond."

Karamoko Niaré, a former postdoctoral researcher in Bailey's lab and first author on the paper, said the team went looking for answers surveillance systems weren't built to catch. "We knew that the parasites were changing so that over time, their susceptibility to malaria treatments was decreasing, and we wanted to know the exact genetic determinants of this shift," Niaré said, per Brown University's statement. Most existing surveillance programs track a known, limited set of resistance markers. This study went with full genome sequencing instead, which is how px1 turned up.

The study was federally funded, according to Brown University.

Why this matters for treatment

Standard malaria treatment in Uganda has relied on artemether-lumefantrine for roughly two decades. As of 2026, the Centers for Disease Control and Prevention has recommended a longer treatment course after standard doses failed to cure several travelers who returned home infected, a sign the parasite is already losing ground to the old regimen, according to Brown University.

A second warning sign, in Ethiopia

A separate, unrelated body of research points to the same broader problem showing up in a different country. Researchers from the University of North Carolina at Chapel Hill, the Ethiopian Public Health Institute, Brown University, the University of Notre Dame and Ethiopia's Ministry of Health surveyed more than 2,200 symptomatic malaria patients at 20 sentinel sites across 11 Ethiopian regions in July and August 2024. The findings were published in the Journal of the American Medical Association, led by Ashenafi Assefa and Jonathan B. Parr, according to News Medical.

That study found rising prevalence of a mutation called pfk13 R622I, linked to partial resistance to artemisinin-based therapies, and growing numbers of parasites with deletions in the pfhrp2 and pfhrp3 genes. Those deletions let parasites dodge detection by the HRP2-based rapid diagnostic tests clinics rely on most.

This comes as Ethiopia's malaria case count exploded, from fewer than 1 million in 2019 to more than 10 million in 2024, according to News Medical.

The Ethiopian researchers explicitly said drug resistance is unlikely to be the main driver of that surge. "Our findings show that malaria parasites carrying drug- and diagnostic-resistance mutations are becoming increasingly common in Ethiopia, raising important concerns for the future of malaria control in the region. At the same time, the data suggest these mutations were not the primary cause of the recent resurgence in malaria cases," Parr said, per News Medical. His team pointed instead to disruptions in malaria control programs and climate shifts as the bigger factors behind the case spike.

That's an important distinction the Ugandan PIN research doesn't address one way or the other, since it wasn't designed to explain case counts, only drug sensitivity. Conflating the two studies into one narrative—resistance mutations equal more malaria cases—would overstate what either one actually shows.

What's unresolved

Bailey's team confirmed the PIN mutation's effect on lumefantrine sensitivity but the full mechanism of how px1 confers resistance still needs work. It's not yet clear whether PIN has spread beyond Uganda into neighboring countries. The CDC's extended-course recommendation for returning travelers suggests U.S. clinicians are already adjusting on the ground. Whether African national malaria programs follow with treatment guideline changes, and how fast, is the next thing to watch.