Resistance to front-line malaria drugs confirmed in Africa

AFRICA – Scientists have confirmed that malaria parasites in Africa have developed resistance to a key family of drugs used to protect against them.

“We’ve all been expecting and dreading this for quite some time,” says Leann Tilley, a biochemist at the University of Melbourne in Australia, who researches the molecular basis of antimalarial resistance.

Signs of drug resistance have long been present in Africa: for instance, in Rwanda between 2012 and 2015, scientists detected the existence of gene mutations associated with resistance in malaria parasites.

A new study, published in the New England Journal of Medicine, bolsters these findings by showing that such mutations are causing an observable drop in antimalarials’ ability to quickly treat people with the disease.

The ‘gold standard’ treatments for malaria — the drug family including artemisinin and its derivatives — are often administered alongside ‘partner’ drugs in what are called artemisinin-combination therapies (ACTs), because multiple drugs are more difficult for parasites to develop resistance against.

The first signs of resistance to artemisinin and its relatives appeared in Cambodia in the early 2000s. Within a few years, malaria parasites in southeast Asia began to evade some of the partner drugs in the ACTs, too, rendering some of the most effective drug cocktails against malaria useless in the region and sending public-health officials scrambling to find combinations that still worked.

For resistance to now hit Africa is particularly dire where more than 90% of malaria cases and deaths worldwide occur. 

Also concerning is that the study found evidence that resistance in Africa arose independently of the resistant parasite strains in southeast Asia, meaning the strains now in Africa might continue evolving to culminate in a ‘super resistant’ parasite that becomes dominant.

Scientists fear that a similar scenario to the one in southeast Asia will unfold in Africa, he says — and in light of the lack of access to adequate health care in many parts of sub-Saharan Africa, it could exact a huge toll.

Although the WHO has mounted an aggressive campaign to eliminate resistant parasites in areas of southeast Asia by rapidly deploying ACTs in sick individuals, the same approach is unrealistic in sub-Saharan Africa given how widespread the disease is there, says Pascal Ringwald, who leads the WHO Global Malaria Program’s Drug Resistance and Containment Unit.

This study puts even more pressure on researchers and drug makers to find another viable treatment or a vaccine for malaria, in case there is more evidence that ACTs are failing in the future.

 Several malaria vaccines are under development, one of which showed promising results in a small clinical trial earlier this year.