Increasing evidence shows that a large fraction of people who seek treatment for malaria don’t have the disease. A recent randomized trial in Kenya that I conducted with Pascaline Dupas and Simone Schaner uncovered that less than 40 percent of older children and adults who purchase antimalarials from drug stores actually have malaria. Several other non-randomized studies have found similar rates of over-treatment in health clinics and hospitals. These and other studies are telling us that any rational strategy aimed at fighting malaria will have to incorporate diagnostic tools in addition to traditional approaches.
Therefore, as World Malaria Day approaches, I’d like to bring attention to diagnostics—a tool that has been evidently stashed at the bottom of the malaria control toolkit. It is certainly less saliently linked to malaria mortality than bed nets or antimalarial medicines, but its lowly status is arguably at the heart of the inadequate coverage levels of both of these life-saving tools.
The great majority of people treated for malaria in Sub-Saharan Africa self-diagnose and buy medicine from a drug store or pharmacy, bypassing the formal health care system altogether. Many others are treated for malaria in health centers based on clinical symptoms such as fever, as blood tests are extremely rare. Often, the symptoms are the result of a cold, virus or possibly a bacterial infection like pneumonia yet are treated with antimalarial medications.
So what’s the harm in treating someone for malaria when they don’t have it? There is little danger to the individual, because the side effects are moderate. The harm stems from the false impression that they actually have the disease. Erroneous beliefs about malaria can lead to all of the harmful “irrational” behavior that we observe in malaria-endemic populations. Many people continue to not sleep under bed nets, to buy ineffective or sub-standard antimalarials and to take partial, incomplete doses of their regimen. One explanation for low usage of these life-saving tools is that it is difficult for people to learn their benefits when so much uncertainty exists about what is and what is not malaria.
Some argue that such massive overtreatment has fueled the emergence of parasite resistance to previous generations of antimalarials and that limiting overtreatment could help stem resistance to the only remaining effective medicines. What is certain is that this confusion about when an illness is actually malaria has ripple effects, weakening maternal and child health programs and wasting precious millions in foreign aid for malaria control.
Technological innovations in the form of rapid diagnostic tests (RDTs) for malaria have made diagnosis a possibility for remote populations with poor access to quality health care. RDTs are blood tests that give results in 15 minutes and many brands are reliable and easy to use. Before RDTs, a person had to have access to a health facility with a working microscope and a lab technician. Several recent studies with community health workers have found that RDTs can be used effectively by people without formal medical training. Pharmacists could also be trained to administer RDTs to customers.
Malaria diagnostics do not only benefit those stricken with malaria. For example, pneumonia remains a leading cause of death among children under five. Because fever is a common symptom of pneumonia, children are often first presumptively treated for malaria. Only when their symptoms don't improve are other possible causes explored. Pneumonia can progress quickly in children and thus eliminating the possibility of malaria early allows the exploration of other potential diagnoses.
As with so many public health products, developing the technology and increasing access is not enough. Psychological barriers must be reduced as well. In our Kenya study, 65 percent of people who tested negative for malaria went on to buy the medicine anyway. More research into how adherence to test results can be improved is needed and increased access to RDTs will need to be coupled with better information about the importance of malaria diagnosis.
In several months, the Global Fund to Fight AIDS, TB and Malaria is spearheading an innovative intervention to increase access to effective antimalarials by heavily subsidizing Artemisinin Combination Therapies (ACTs) in 10 African countries. Without an increase in use of malaria diagnostics, our results from Kenya suggest that a vast amount of that subsidy money will go to antimalarials for people without malaria. The policy is still likely cost-effective—the bulk of malaria morbidity and mortality is from young children and this subsidy should dramatically increase their access to affordable, effective antimalarials. But there is a great opportunity here for subsidy money to be better targeted and for malaria treatment to be more rational by increasing access to diagnostics.