The global fight against malaria is being threatened by growing resistance to powerful new drugs that were considered one of the most important weapons in the battle.
Experts say the medical effects of artemisinin-based compounds, being used to treat people around the Burma-Thailand border, are weakening. Where there were once apparently miraculous recoveries of children treated with artemisinin combination therapy, now the treatments take longer to be effective. Doctors envisage a time when, if nothing is done, the drugs will cease to work.
Malaria-parasite resistance to the drugs has been identified in western Cambodia, but it was hoped tough controls would contain it. Now scientists say there are real problems in Burma and warn that resistance there must be tackled if it is not to spread worldwide.
They warn that history is repeating itself: resistance is appearing and artemisinin is losing its potency, just as happened with older drugs such as chloroquine, and it is beginning in the same places.
Resistance threatens malaria intiatives
The discovery of resistance to the drugs — which have, with insecticide-impregnated bed nets, altered the course of the malaria epidemic — “threatens worldwide initiatives to control and eliminate malaria”, reports a paper in the Lancet.
The paper is one of two by teams of scientists who have studied the growth of resistance on the Thai-Burmese border.
“Resistance to the previous mainstays of antimalarial treatment, namely, chloroquine and sulfadoxine-pyrimethamine, also arose in western Cambodia and spread across southeast Asia into Africa, resulting in the deaths of millions of children,” it said.
In the other paper, published in the journal Science, scientists in southeast Asia and the United States identified a major region of the malaria parasite genome associated with artemisinin resistance. This link could allow researchers to map resistance and help to prevent its spread.
Nick White, chair of the Worldwide Antimalarial Resistance Network and an author of each of the papers, said there were rumours that resistance might have spread to Burma. Said White, a professor who is also chair of the Wellcome Trust’s southeast Asia major overseas programmes: “There is no doubt there has been quite significant reduction in susceptibility to artemisinin. The problem is once it gets to Burma, because it is the gateway to the West. Malaria control in Burma is much weaker than in the rest of the region. It is going to be much more difficult to contain it.”
Because of the political situation, Burma did not get the same levels of funding for malaria control as other countries.
Misuse of the drugs in Asia has allowed parasitic resistance to develop and the sale of single artemisinin pills, which should be taken in combination with other drugs, has been a disaster. “It is pretty clear that the widespread availability of substandard counterfeit drugs and monotherapies is what has driven this,” White said.
He said more information on the spread of resistance was vital. If this was a flu pandemic, the West would be mobilising all its forces, but too little was being done despite the consequences.
“Is the response appropriate to the threat? I don’t think so. We really need to scale up. It is going to require an international effort.” —