Urgent action is required to combat rising antimalarial resistance in Africa, health experts have warned.
Artemisinin-based combination therapies (ACTs) have been the first-line treatment for malaria for almost 20 years.
But resistance to artemisinin in malaria-causing Plasmodium falciparum parasites in eastern Africa is rising, meaning a surge in malaria-related sickness and death in the region could be imminent.
ACTs have significantly reduced the global burden of malaria. However, resistance, first seen across South-East Asia, has spread quickly, posing a significant public health emergency.
Dr Lorenz von Seidlein, professor of global health at the University of Oxford, told The National that while ACTs remain effective in many regions, there have been reports of partial resistance to artemisinin in South-East Asia and parts of Africa.
“Artemisinin resistance was first reported in Cambodia in 2008,” he said.
“Resistant parasites have been detected in eastern Africa over the last five years, but the genetic mutations are different from the ones described in SE Asia suggesting the independent emergence of genetic mutants.”
It is vital to replace ACTs with fully effective drugs, he added.
Adding a third drug is an approach that has worked well, said Dr von Seidlein, who wrote about the urgency of the issue with colleagues in an article published in the American Association for the Advancement of Science journal.
“Instead of combining the rapidly acting artemisinin with a single partner drug we combine it with two partner drugs, for example artemether-lumefantrine plus amodiaquine,” he added.
The same approach is followed in tuberculosis and HIV to provide mutual protection against resistance.
But longer-term strategies are also required, including strengthening surveillance systems, ensuring the availability of high-quality drugs, promoting adherence to treatment protocols, and investing in research and development of new antimalarials.
Malaria kills more than 400,000 people each year, including more than 260,000 aged under five in sub-Saharan Africa.
The disease is caused by a single-cell parasite, Plasmodium falciparum, which is neither a virus nor a bacterium, and is transmitted to people by infected mosquitoes.
When a mosquito injects a person with anticoagulant saliva – which stops their blood from clotting – a form of the parasite known as a sporozoite is also transmitted into the person’s bloodstream.
Sporozoites travel to the liver, where they multiply, before entering red blood cells and replicating further, releasing another form of the parasite.
Disease symptoms, which include fever, fatigue, headaches and chills, are caused by the parasite’s effects on red blood cells.
Subsequently, mosquitoes are infected when they ingest yet another form of Plasmodium falciparum when they feed on the blood of infected people, and the cycle continues.
