For two decades, Africa has been winning its fight against malaria, largely on the strength of two tools: a fast-acting plant-derived drug and insecticide-treated bed nets. Together, they helped cut malaria cases across the continent by 70 per cent between 2000 and 2015, one of public health’s genuine success stories. 

Now a new World Health Organization (WHO) report shows both weapons are starting to lose their edge, and the cracks are appearing closer to Kenya than many people realise. Drug-resistant parasites have already been confirmed in three of Kenya’s neighbours, mosquitoes are growing resistant to the insecticide used on standard bed nets, and an invasive mosquito species has reached Kenyan cities. None of this means Kenya’s own malaria treatment has failed, but it does mean the safety margin around it is narrowing. 

The drug at the centre of the story is artemisinin, the backbone of modern malaria treatment. It is fast-acting and, when combined with a second, slower drug, clears the malaria parasite from the body quickly and reliably. This combination is called an ACT, short for artemisinin-based combination therapy, and it is what doctors across Africa reach for first when someone tests positive for malaria. 

 Kenya’s version is a drug called artemether-lumefantrine. Testing done in western Kenya between 2016 and 2017 found the treatment failed in fewer than 10 per cent of cases, a good result. 

The drug’s effectiveness depends on the malaria parasite staying vulnerable to it, and in a growing number of countries, that is no longer guaranteed. Like bacteria that can become resistant to antibiotics, the parasite that causes malaria can evolve to survive drugs that once killed it. Scientists track this by looking for genetic markers in a part of the parasite called the kelch13 gene.  

Drug resistance giving parasites more time to survive and spread malaria, straining second drug in the combination 

When a marker linked to resistance is confirmed through lab testing, that country is recorded as having artemisinin partial resistance, meaning the parasite takes longer to clear from the body, giving it more time to survive and spread, and putting extra strain on the second drug in the combination, which then has to do more of the work alone. Over time, that second drug can start failing too. 

Confirmed resistance has now been found in four African countries: Rwanda, Uganda, Tanzania and Eritrea, three of which, Uganda, Tanzania and Rwanda, are Kenya’s direct neighbours or close regional partners. A fourth group, including Ethiopia and the Sudan, is showing signs that make scientists suspicious enough to flag them as likely cases too. Five of the eight African countries with confirmed or suspected resistance sit in East Africa or the Horn of Africa, the same region as Kenya, meaning the parasite carrying resistance genes is active in countries whose citizens cross into Kenya regularly, and vice versa, for work, trade and family visits. 

The first confirmed case on the continent was in Rwanda in 2014. It would be simpler if resistance had spread outward from there as ripples from a stone dropped in water. Instead, separate outbreaks appeared independently in different countries, with Eritrea, Ethiopia, Uganda, the Sudan and Tanzania all developing their own resistant strains from around 2016 onward, largely without one country infecting another.  

This matters for Kenya specifically because it means new resistant strains could, in theory, develop inside its own borders too. Eritrea’s resistance marker, known as R622I, has been found in parasites that also dodge the standard rapid diagnostic test many clinics rely on to confirm malaria in the first place. 

Bed nets treated with insecticide have been one of Africa’s most effective malaria tools, credited with preventing millions of cases since 2000. But the mosquitoes carrying malaria are becoming resistant to pyrethroids, the main insecticide used on those nets. According to the WHO report, pyrethroid resistance has now been confirmed in 91 per cent of countries that monitor for it. 

 Invasive mosquito species called Anopheles stephensi thrives in cities, is resistant to insecticides 

In response, health programmes have started switching to newer nets treated with two different chemicals instead of one, so mosquitoes resistant to one compound are still caught out by the other. These dual-ingredient nets made up just 8 per cent of net deliveries in 2022; by 2024, that figure had jumped to 47 per cent. They cost more, but given what is at stake, the switch looks less like an upgrade and more like a necessary defence of gains already made. 

There is a second mosquito problem layered on top of this. An invasive species called Anopheles stephensi, which thrives in cities and is already resistant to several insecticides, has been spreading across Africa since it was first detected on the continent in Djibouti in 2012. It reached Ethiopia and the Sudan by 2016, then Somalia, Nigeria, Eritrea and Yemen, and arrived in both Ghana and Kenya in 2022. 

Resistance to an older malaria drug, chloroquine, first appeared on the Cambodia-Thailand border in 1957 and eventually spread across Africa, contributing to a malaria crisis that lasted decades. Artemisinin resistance began the same way, first confirmed in western Cambodia in 2008. That region, the Greater Mekong subregion, has since become a case study in what determined action can achieve: sustained investment and early containment efforts helped drive down malaria cases there by 77 per cent and deaths by 97 per cent between 2012 and 2022. 

The open question the WHO report raises is whether that same success can be repeated in Africa, where far more people are exposed to malaria and health systems generally have fewer resources to respond with. If resistance across Africa were to reach the levels once seen in Cambodia, the continent could see an additional 78 million malaria cases over five years, and by 2060, treatment failure rates could climb to around 31 per cent, meaning more than 50 million treatments failing in a single year. 

Right now, ACTs still cure the vast majority of malaria infections across Africa, including in Kenya. What the modelling shows is a widening gap between where things currently stand and where they could end up if resistance is left unchecked. 

WHO three-pillar strategy: genetic testing, routine drug efficacy, protecting access to drugs that work   

The WHO report estimates that malaria programmes across Africa received just $3.9 billion in 2024, against an annual target of $9.3 billion. That shortfall has already led to some planned surveillance surveys, the very tools scientists use to catch resistance early, being delayed or cancelled altogether. 

The WHO’s current strategy rests on three pillars: genetic testing to map where resistance markers are appearing, routine drug efficacy tests to check treatments are still working, and protecting access to the medicines that do still work while alternatives are developed.  

One such alternative is already in the pipeline: a new combination drug called ganaplacide-lumefantrine, created by Novartis together with the Medicines for Malaria Venture, would be the first major malaria treatment that does not rely on artemisinin at all. But new drugs take years to move from trials to pharmacy shelves, which is why early detection and containment now carry so much weight. 

Kenya is not currently facing confirmed drug-resistant malaria within its borders. Its national treatment still works, its surveillance systems are active, and bed net coverage remains high. But it is sitting inside a region where resistance has now been confirmed in three neighbouring or nearby countries, and suspected in two more. 

Sources: WHO malaria resistance report; western Kenya drug efficacy testing, 2016 to 2017; Greater Mekong subregion malaria data, 2012 to 2022; Novartis and Medicines for Malaria Venture. 

Data visualisation by Stanley Njihia 

Text by Yvonne Kawira