Malaria experts made it clear: though control programs have made significant achievements over the past decade, continuing on the same path will not lead the world to malaria eradication.
Leaders in the malaria field convened at Harvard University to discuss how to make the shift from control to eradication at a forum and symposium entitled “Rethinking Malaria,” hosted by the university’s Institute for Global Health and School of Public Health, with support from the ExxonMobil Foundation. Scientists, health ministers, heads of malaria programs, economists, and corporate CEOs discussed challenges that will arise as malaria programs move from control to elimination, and what will be required to address the changing needs.
Since the failure of the first malaria eradication campaign in 1969, most efforts have focused on malaria control–decreasing the morbidity and mortality caused by the disease. Current prevention and treatment methods reduce malaria transmission, but are unlikely to stop it altogether, even if they achieve high coverage in all endemic areas. While control and eradication strategies both have the goal of alleviating human suffering, they require different approaches.
Experts at the Rethinking Malaria meeting identified several key areas where research is needed to achieve elimination and eradication:
- Plasmodium vivax. Public health professionals have focused on malaria caused by Plasmodium falciparum because it causes the most deaths. Though people in the Americas, Africa, and Asia also suffer from Plasmodium vivax malaria, it has not been well studied. In order to achieve eradication, more research on control of this form of malaria is needed. P. vivax infection is particularly challenging, as parasites can remain in the liver for months or even years.
- Asymptomatic infection. Some people have malaria parasites in their blood and yet have no symptoms of malaria. It will be essential to learn more about these asymptomatic carriers, as they can continue to pass on the disease. New diagnostic tools that can detect low parasite levels may be needed.
- Surveillance in low-transmission settings. To stop malaria transmission completely, all cases must be detected and treated quickly. While surveillance systems currently monitor for malaria, they were designed for high-burden areas. New techniques that are sensitive enough to detect low-level transmission are needed. Case detection and mapping methods that have been developed for other infectious diseases should be investigated and adapted for use with malaria, if possible.
- Decreasing natural immunity. In malaria-endemic areas, people become semi-immune to malaria through repeated exposure to the parasite. As cases of malaria become rarer, people will not build up this immunity and may become more susceptible to severe disease when they are exposed. Communities will need to be aware of the danger of serious complications in healthy adults, a population not normally affected by severe malaria. Likewise, health centers will need to be prepared to address the changing burden, possibly with new treatment methods. Researchers should closely monitor epidemiological trends in countries that have recently accomplished large malaria reductions in order to understand how this success will affect transmission and illness.
On the path towards eradication, malaria will continue to present new challenges even as gains are made. Some will be unanticipated, but others have been identified by experts and were laid out at this high-level meeting. Funders should support research in these areas to ensure that the current malaria eradication campaign is the final one.