Scientists warn of resistance to antimalarial drugs in Africa | Overall health



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Antimalarial drug resistance in Africa may start to take hold, according to a study that maps changes similar to those seen a decade ago when drug resistance spread across Southeast Asia.

In Cambodia and neighboring countries, artemisinin-based drug compounds widely used against malaria are no longer always effective. Falciparum malaria parasites have developed genetic mutations that allow them to evade drugs. There are serious fears that drug resistance is spreading to Africa, which has the heaviest burden of malaria cases – and the highest number of child deaths as a result.

A study in Rwanda, published Wednesday in the Lancet Infectious Diseases journal, shows that the feared erosion of the effectiveness of antimalarial drugs may have started. As happened in Southeast Asia, researchers found that giving a child treatment with artemisinin doesn’t always clear the malaria parasites from their blood in three days, as it should.

Artemisinins, introduced in the early 2000s in China, are given in combination with another type of antimalarial drug to ensure that all parasites are eliminated and that the effectiveness of the drugs is not compromised. The most common combination is artemether-lumefantrine, which Rwanda started using in 2006.

If the artemisinin drug does not clear the parasites quickly within three days, the partner drug is under pressure and resistance to it in turn may develop. At this point, treatment may fail, as has happened in Southeast Asia.

“Mutations can emerge spontaneously and previous studies have shown isolated cases of resistance. However, our new study shows that resistant isolates are starting to become more common and, most importantly, are associated with clinical implications. [delayed parasite clearance]Says lead author Dr Aline Uwimana from the Rwanda Biomedical Center in Kigali.

Experts called for more intensive surveillance of drug resistance in Rwanda and other African countries. “Our study showed that the treatment of malaria in Rwanda is still 94% effective, but further studies and continued surveillance are urgently needed,” said co-author Dr Naomi Lucchi, CDC resident advisor for the disease. ‘US President’s Initiative Against Malaria.

Researchers monitored the treatment of 224 children with malaria aged six months to five years in three regions of Rwanda – Masaka, Rukara and Bugarama. At two of the sites, about 15% of the children still had detectable parasites after three days, which meets the World Health Organization (WHO) criteria for partial resistance.

The researchers also found certain mutations in the parasites, which are implicated by the WHO in delayed clearance.

Experts believe the warning signs are there. This study, along with other data, suggests that we are “on the verge of having clinically significant artemisinin resistance in Africa, as emerged in South East Asia over ten years ago” , writes Professor Philip Rosenthal, of the University of California at San Francisco, in a journal commentary.

“Loss of effectiveness of key ACTs [artemisinin-based combination therapies], especially artemether-lumefantrine, the most widely used antimalarial, could have dire consequences, as happened when resistance to chloroquine led to huge increases in late malaria deaths. of the 20th century.

It was impossible to predict the pace of the advance in Africa, but close monitoring of the development of resistance in the parasite – with rapid replacement of failed diets – “could save many lives,” he said.

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