By luck of geography, malaria does not occur in the United Kingdom. When patients go to the doctor in the UK for malaria treatment, it’s always because they have recently traveled to an endemic region and brought it back with them. Sick patients see a doctor, who diagnoses malaria and prescribes a simple, cheap, and effective malaria treatment. The patient agonizes for a few days, but fully recovers.
At least, that is how it’s supposed to work. But according to a new scientific paper, four patients diagnosed and treated for malaria in the United Kingdom between October 2015 and February 2016 saw their disease rebound months or weeks later. Their malaria was drug resistant. And this raises an entirely new set of questions–and challenges some commonly held assumptions– about malaria in Africa.
Drug resistant malaria is not a global health emergency – yet – but these cases remind us of the challenges that stand in the way of effective malaria treatment and effective data collection in developing countries.
Malaria is a complex disease. It is transmitted by mosquitoes that are host to a specific kind of parasite, parasitic protozoans of the Plasmodium type. It can be prevented by avoiding mosquito bites through spraying or bednets, or by taking anti-malarial drugs as a preventative measure. About 300,000 people die of malaria every year, mostly children and pregnant women. Globally, a child dies of malaria every two minutes.
Anti-malarial drugs are essential in many parts of Africa and Asia. Their frequent use is medically necessary, but that necessity does not stop resistance from developing. Just as with antibiotics, the more often anti-malarial drugs are used, the more quickly the microorganisms they target evolve to survive.
The World Health Organization (WHO) tracks malaria cases and what treatments they respond to, and recommends standard first and second-line treatments for every country. The standard treatment regimen in most locations is now a two-drug combination known as artemether-lumefantrine, which came into use after malaria parasites began to evolve resistance to single-drug treatments.
It is this combination regime, artemether-lumefantrine, which failed in the four patients in the UK. All four patients were prescribed the regime after initial malaria diagnosis, and all four required additional treatment when it became clear that artemether-lumefantrine was not working. There are about 2,000 cases of malaria diagnosed every year in the UK, but to date malaria has not actually been transmitted in the country. All diagnosed cases were infected elsewhere and then travelled to the UK before diagnosis.
The patients infected with resistant malaria, diagnosed between October 2015 and February 2016 and discussed in a recent issue of Antimicrobial Agents and Chemotherapy, had traveled to different parts of Africa – Angola, Liberia and Uganda. The second-line malaria treatments succeeded in all cases and the patients survived. There was no threat to public health in the UK.
Still, these cases are distressing not for their UK connection, but because of what they indicate about malaria in Africa. Health data collection is still weak in many African countries, the result of poorly funded health systems and overburdened health care personnel. Effective disease surveillance is difficult to implement, especially for endemic diseases such as malaria. This is compounded by the availability of malaria drugs; they are freely available in pharmacies. While this does increase access to treatment, it also means that many patients with malaria never enter the health care system and can’t be counted or tracked.
If patients infected in Africa are being diagnosed with resistant malaria in the UK, that means there is a lot of resistant malaria being transmitted in Africa. These four patients represent a tiny fraction of the number of people who are infected with malaria every year. The article in Antimicrobial Agents and Chemotherapy mentioned that patients infected with resistant malaria after travel to Africa are being diagnosed in Sweden as well as the UK. In addition, Uganda, Liberia, and Angola are not neighboring countries. If resistant malaria is found all three of those countries, that means it is very likely to be found throughout all of sub-Saharan Africa.
Drug-resistant malaria is already widespread in Southeast Asia, where it is a serious problem. The standard malaria treatment in the region now requires three different drugs to be effective, not just two. Sub-Saharan Africa, however, is home to a different variant of the malaria parasite. It has not evolved in the same way as the Asian parasite.
These cases of resistant malaria are a warning that Africa is now beginning to face the same resistance challenges observed in Southeast Asia. Global Health experts have suspected for some time that this is the case. It has been known for some time that the African malaria parasite is capable of evolving the same kinds of resistance measures that are found in Asian parasites. Isolated cases of resistant malaria have been reported with increasing frequency in African countries, but poor disease surveillance has made reliable data unavailable.
The UK was never at any immediate risk from these cases. Its mosquitoes do not carry malaria, and no one has been infected on its soil. Malaria is dangerous, but not immediately incapacitating. It is not surprising that people with malaria are capable of flying home. All four cases were treated effectively for malaria, and did not cause any disease transmission.
The concern here is for the patients who didn’t fly home to the UK. There were between 133 million and 273 million cases of malaria in sub-Saharan African in 2015. 292,000 of those cases were children who died of the disease. How much worse will those numbers get when resistant malaria becomes the norm?