Researchers have found for the first time “disturbing” evidence that a life-saving malaria drug is becoming less effective in young African children with severe infections.
A study of children being treated for malaria in hospital in Uganda, presented at a major conference on Thursday, found signs of resistance to artemisinin in one in 10 patients.
Antimicrobial resistancewhere pathogens such as parasites, bacteria and fungi develop ways to evade the drugs used to fight them is a growing global concern. It is prediction to kill more than 39 million people by 2050.
Children are most vulnerable to malaria, with about 450,000 under-5s die from the disease every year in sub-Saharan Africa. Of the 100 children studied, 11 showed partial resistance to the treatment. All are infected by malaria parasites that carry genetic mutations linked to artemisinin resistance.
Dr Chandy John, from Indiana University, who co-authored the study with international colleagues, said: “This is the first study from Africa to show that children with malaria and clear signs of severe disease experience at least partial resistance to artemisinin .”
Another 10 of the children studied, who were thought to have been cured of infection, had a repeat attack of the same type of malaria within a month. The results suggest that the “gold standard” treatment they received, which combines artemisinin with a second antimalarial drug called lumefantrine, did not work as well as it should have.
John said the study was started after researchers noticed a slow response to treatment in some children already being monitored for a project on severe malaria in young patients.
“The fact that we started seeing evidence of drug resistance before we even started specifically looking for it is a worrying sign,” John said.
“We were further surprised that, after focusing on resistance, we also ended up finding patients who had recurrence after we thought they were cured.”
The study is being presented at the annual meeting of the American Society of Tropical Medicine & Hygiene in New Orleans and published in the Journal of the American Medical Association.
John said it is too early to determine how widespread resistance to artemisinin is in Africa, although there is evidence that it is spreading, suggesting studies showing partial resistance in children with uncomplicated malaria – a milder form that does not affect organs – in countries such as Rwanda and Uganda.
However, he said: “I think our study is the ‘canary in the coal mine’ for children with severe malaria.”
Resistance to artemisinin therapies has emerged earlier in Southeast Asiawhere the first signs were identified in similar studies. Treatment failure rates in that region increased as resistance also emerged to drugs used in combination with artemisinin. Dr Richard Pearson, from the Wellcome Sanger Institute, who was not involved in this study, said the situation in East Africa is reminiscent of the situation in South-East Asia 15 years ago.
Artemisinin is used in a variety of forms to treat the disease. For children with severe malaria, it consists of an intravenous infusion of artesunate, one derivative of artemisinin, followed by an oral drug that combines a second derivative with another antimalarial drug.
Artesunate replaced quinine as the recommended treatment for children with severe malaria more than a decade ago, after a trial showed fewer deaths with the newer drug. “Going back to quinine would be a step backwards,” John said.
Dr Alena Pance, a senior lecturer in genetics at the University of Hertfordshire, said any indication of resistance to the “critical drug” was extremely worrying and that high transmission rates in Africa posed a dangerous risk of rapid spread of resistance within the continent. . makes these findings even more alarming”.
