– raises concern over growing resistance to artemisinin, a key component of the medicines used to treat malaria.
Nigeria must strengthen malaria drug-resistance surveillance before treatment failure becomes widespread
A new study published in The Lancet Infectious Diseases has warned that artemisinin partial resistance is spreading rapidly in parts of Africa, raising concerns that some of the continent’s most important malaria medicines could eventually lose their effectiveness.
The study, which analysed nearly 186,000 malaria parasite samples from 47 African countries, found that genetic markers associated with artemisinin partial resistance have expanded from isolated pockets into established regional hotspots, particularly in East Africa.
The researchers said the development is worrying because resistance to artemisinin could be followed by resistance to the partner drugs used in artemisinin-based combination therapies (ACTs), potentially creating a situation similar to that which preceded widespread malaria treatment failure in Southeast Asia.
The study, published online on July 7, 2026, mapped the prevalence and geographical spread of molecular markers of resistance in Plasmodium falciparum, the parasite responsible for the most deadly form of malaria.
The researchers combined data from 578 studies and 3,848 distinct surveys, involving 185,099 samples tested for resistance-associated mutations in the k13, crt and mdr1 genes.
They identified 11 validated and seven candidate k13 mutations associated with artemisinin partial resistance across 18 African countries.
Resistance hotspots emerging
According to the study, resistance did not appear to be spreading from a single African source. Instead, several mutations appear to have emerged independently in different locations.
The researchers identified distinct emergence of the k13 R561H mutation in Rwanda; A675V and C469Y in Uganda; and R622I in Ethiopia and Eritrea.
The most striking increase was recorded in Rwanda’s Northern Province, where the model estimated that the prevalence of k13 artemisinin-resistance mutations reached 62.2 per cent in 2024, compared with just 0.2 per cent in 2012.
The area in Africa where the researchers were more than 80 per cent confident that resistance prevalence exceeded five per cent also expanded substantially—from about 3,919 square kilometres in 2014 to more than 202,000 square kilometres in 2024.
The researchers stressed that the modelling does not mean every parasite in these areas is resistant, nor does the presence of a molecular marker automatically mean that a malaria treatment will fail.
Rather, the genetic markers provide an early warning of parasites becoming less susceptible to artemisinin.
Why partner drugs matter
The researchers said artemisinin partial resistance becomes particularly dangerous when resistance to the second drug in an ACT also develops.
ACTs work by combining a rapidly acting artemisinin derivative with a longer-acting partner drug. Artemisinin rapidly reduces the parasite burden while the partner drug eliminates remaining parasites.
The study found that some mutations associated with reduced susceptibility to the partner drug amodiaquine are declining in parts of Africa, while the crt K76T mutation remains prevalent in the Horn of Africa.
At the same time, the widespread use of artemether-lumefantrine has altered the genetic landscape of the parasite, with some mutations associated with amodiaquine susceptibility declining as lumefantrine use becomes more widespread.
The authors warned that this does not mean lumefantrine resistance has already become widespread. However, they noted emerging evidence of reduced ex-vivo lumefantrine susceptibility in Uganda and the Democratic Republic of the Congo, as well as reports suggesting that partner-drug resistance may be emerging.
This combination of developments, they said, is reminiscent of the conditions that preceded widespread ACT failure in Southeast Asia.
The Nigeria lesson
For Nigeria, the study should be viewed as an early warning rather than evidence that artemisinin resistance is already widespread in the country.
Nigeria was included among the African countries represented in the overall dataset, but the paper’s major resistance hotspots were concentrated in East Africa and the Horn of Africa.
The more important lesson for Nigeria is therefore the need to detect resistance before it becomes a clinical treatment-failure crisis.
The researchers emphasised that molecular surveillance is essential because genetic changes can provide an early signal of emerging resistance, while therapeutic efficacy studies can establish whether those changes are translating into actual treatment failure.
For a country carrying one of the world’s largest malaria burdens, that distinction is critical.
Nigeria’s malaria programme cannot afford to wait until large numbers of patients are failing treatment before investigating whether parasite resistance is developing.
The Lancet study therefore points to several priorities.
First, Nigeria needs stronger molecular surveillance of malaria parasites. Genetic testing should be integrated more systematically into malaria surveillance so that resistance-associated mutations can be detected and tracked geographically over time.
Second, molecular surveillance should be linked to therapeutic efficacy studies. The presence of a k13 mutation alone does not prove clinical treatment failure. Researchers need to combine genetic data with laboratory susceptibility testing and patient outcomes to determine whether ACT effectiveness is actually declining.
Third, Nigeria needs better sharing and integration of malaria resistance data. One of the major problems identified by the researchers was that molecular surveillance data are scattered across different studies and repositories, often using different sampling and sequencing methods. A harmonised national database would make it easier to identify emerging hotspots.
Fourth, surveillance should extend beyond Nigeria’s borders. Malaria parasites do not respect national boundaries. The rapid geographical expansion observed in East Africa demonstrates why countries need to monitor neighbouring regions and share information.
‘Do not wait for treatment failure’
The researchers said their modelling framework can help national malaria programmes identify areas where resistance is likely to be established and prioritise those locations for further genetic surveillance and therapeutic efficacy studies.
Importantly, they cautioned that the model cannot reliably predict future resistance because it was designed primarily to interpolate existing data rather than make forward projections.
The study also acknowledged major surveillance gaps across Africa. In poorly sampled areas, the absence of a resistance marker should not automatically be interpreted as proof that resistance is absent.
For Nigeria, this is perhaps the most important message: absence of evidence is not evidence of absence.
The researchers concluded that strengthening molecular surveillance, integrating genomic and laboratory data, and evaluating alternative treatment strategies—including triple ACTs and new drug combinations—will be crucial to containing the growing threat.
Africa has already experienced the consequences of losing effective malaria medicines in the past. The new evidence suggests that the continent may be entering another critical phase.
For Nigeria, the warning is clear: the time to look for artemisinin resistance is before malaria treatment begins failing on a large scale, not afterwards.
