Malaria is endemic in over 100 countries around the world, and the World Health Organization (WHO) estimates that approximately 3.4 billion people are exposed to it. Transmitted to human hosts via the bite of infected female Anopheles spp. mosquitoes, the parasite can then develop in a variety of ways – species include P. vivax, P. ovale and P. falciparum, and the particular species will determine the appropriate treatment and choice of medication (referred to as chemoprophylaxis).
Up until recently, global malaria prevention efforts were relatively successful, largely through chemoprophylaxis and other measures such as mosquito nets impregnated with insecticide. More recently, however, calls to effectively stamp out the disease have taken on renewed urgency, as leading experts have said that the parasites are rapidly becoming resistant to traditional drugs, spelling a potential disaster in vulnerable areas such as Africa and Southeast Asia. At the heart of treatment and control programmes are artemisinin drugs, derived from traditional Chinese medicine, but malaria parasites with a resistance to these drugs are becoming worryingly common in border regions of Southeast Asia. Studies suggest that these parasites will inevitably spread to India, and experts fear that when they reach Africa – and it is highly likely that they will – deaths from the disease will skyrocket. “Frontline ACTs [artemisinin combination therapies] are still very effective at curing the majority of patients,” said Doctor Elizabeth Ashley, of Thailand’s Mahidol Oxford Tropical Medicine Research Unit (MORU), which carried out a recent study of spreading malaria resistance. “But we need to be vigilant as cure rates have fallen in areas where artemisinin resistance is established. Action is needed to prevent the spread of resistance from Myanmar into neighbouring Bangladesh and India. The artemisinin drugs are arguably the best antimalarials we have ever had. We need to conserve them in areas where they are still working well.”
Writing in the UK’s Guardian newspaper, Professor Nicholas White, an authority on malaria, suggested that the time had come for extreme measures, and that dosing everybody in endemic regions, whether they were suffering from the disease or not, would be necessary to eradicate malaria before artemisinin drugs become useless. “It is undeniably a huge challenge,” he said, “malaria is worst in remote rural areas, where people are most difficult to reach and treat, and it has had a chequered history – which may be why health authorities have yet to accept it. But it might just be possible, and it might work, and so growing numbers of experts, myself included, believe we should try it. However difficult, it is our last hope for artemisinin. Unfortunately the window of opportunity is closing fast as resistance spreads and potentially worsens.”
Doctor Jeremy Farrar, director of the Wellcome Trust, a global charitable foundation ‘dedicated to achieving extraordinary improvements in health’ which funds MORU, also added his voice to the debate: “If resistance spreads out of Asia and into Africa, much of the great progress in reducing deaths from malaria will be reversed. Our ability to respond to these rapidly emerging health problems depends on swift gathering of evidence, which can be quickly translated into public health and clinical interventions that are then implemented. Antimicrobial resistance is happening now. This is not just a threat for the future, it is today’s reality.”
Organisations such as WHO, the US Centers for Disease Control and Prevention and the UK’s National Travel Health Network and Centre maintain regular updates on levels of malaria in endemic countries, and travellers concerned about the disease are advised to keep an eye on developments, and to maximise prevention and mosquito bite avoidance methods when travelling.
“Across clinical medicine,” Professor White concludes, “we have underestimated the threats posed by new infections – including bird flu, the MERS coronavirus, SARS and the current Ebola outbreak – and we have been complacent about the loss of life-saving anti-infective drugs to resistance. These micro-organisms are becoming resistant faster than we can develop drugs to stop them. Let’s hope we can stop history repeating itself at a cost of millions of children’s lives.”