Eliminating Malaria in Africa Could Accelerate the Continent's Development

Malaria is preventable, treatable and curable, but up to 500 million cases of the mosquito-born disease occur each year killing more than a million people. Transmission is highest in sub-Saharan Africa, where its elimination could move the continent toward development. But problems getting anti-malarial medications, insecticides and other preventive tools to people at risk are often to blame for malaria's continued presence in Africa, two experts said in a presentation at AAAS.

Ripley Ballou, deputy director of infectious disease at the Gates Foundation, and Steven Phillips, medical director in global issues and projects for ExxonMobil, explored the complex challenges still posed by malaria during a salon-style discussion at AAAS that was moderated by National Public Radio reporter Joe Palca. While the disease has been eradicated in the United States, it continues to be rampant in tropical and subtropical regions, including sub-Saharan Africa, Latin America and Southeast Asia.

"You'd think that if it is preventable and curable, the problem would go away," said Francis Slakey, co-director of Georgetown University's Program on Science in the Public Interest. Slakey, who developed the "Global Challenges" discussion series as part of his class at Georgetown University viewed the persistence of the disease as an opportunity to explore an example of where science ends and where other problems begin.

Malaria outbreaks can be considered a litmus test for economic development and social instability. In fact, the World Health Organization reports that up to 30% of malaria deaths in Africa occur due to a war, local violence or other emergencies. Most malaria victims are young children in sub-Saharan Africa, according to the Centers for Disease Control and Prevention.

"I think malaria is the No. 1 disease of this decade," said Phillips. The disease tests the ability of nations to cooperate, making it "much more than a biomedical issue or public health issue."

He became involved in malaria issues in 2000, when the oil companies Exxon and Mobil merged and he was asked to identify any new significant risks that would face the new conglomerate's physical assets, operations and human resources. With the combined Exxon and Mobil assets, Phillips found that the company would be "huge" in Africa. About one eighth of the world's oil would be coming from Africa over the next decade, he said, and about 90% of the more than 4000 ExxonMobil employees in Africa were local Africans.

"A quick and dirty medical risk assessment showed surprisingly that malaria was the No. 1 risk faced by our employees," Phillips said at the 27 October discussion at AAAS. The toll in sickness and death harms workers, their families and their communities, and that obviously hurts the company's operations.

"This was the No. 1 threat to our day-to-day operations," he said, adding that ExxonMobil became interested in malaria due to "enlightened self-interests."

Tackling the preventable, treatable, curable disease "sounded like low-hanging fruit," Phillips said, but it proved to be far from straightforward. "The mosquito does not respect fencelines," he said, acknowledging that control programs limited to the workplace alone would not work. "We had to impact communities in country scale and in fact continent scale if we were going to make a difference."

Ballou said that about a year ago the foundation's initiative to eradicate malaria began when Bill and Melinda Gates addressed a forum of malaria researchers and said they wanted to take steps to rid the globe of the disease. "It was a life-changing moment for many people in that room," said Ballou, who has spent most of his professional life working on malaria vaccines. "While the foundation had already made many substantial investments aimed at preventing deaths caused by malaria, here was a real call to action to take a global view and really begin talking about eradication," he said. Eradication is a "touchy subject" in the malaria world, Ballou said, because previous attempts had not succeeded. For example, malaria was eliminated and then returned in Sri Lanka.

The infectious disease expert gave the AAAS audience a quick tutorial on the biology of malaria, a disease caused by a parasite and shared between humans and mosquitoes. Mosquitoes—known as a malaria vector—harbor the Plasmodium parasite and pass it on to humans through insect bites. But only particular mosquitoes are malaria vectors: female mosquitoes of the Anopheles genus.

Many species within Anopheles can transmit malaria, but particular species that are very efficient at transmitting it. Ballou said that the parasite has a biologically complex life cycle in both mosquitoes and humans. Malaria begins in the liver in a weeklong silent phase, and then clinical symptoms emerge, including fever and headache. The disease can lead to death relatively quickly in people who don't have immunity, Ballou said. Eradication involves eliminating the parasite in either humans or mosquitoes for long enough—around 100 days—to stop transmission.

While Ballou said that eradication is a far-off goal today, he identified five approaches that the Gates Foundation is taking toward eliminating the disease: better vaccines; better vector control; better ways to implement existing tools to control malaria (drugs, insecticides, bednets); better diagnostics to catch malaria-infected patients; and improved advocacy. "It's very important that we get this message out that this is a global problem, there are ways to tackle it, and we all need to work together to do this," Ballou said.

"How much will be solved technologically versus geopolitically?" asked Palca, the moderator.

Ballou said it will take equal parts technology and global politics to eradicate malaria, adding that experts at the Gates Foundation recognize that the importance of geopolitics even if the foundation is investing in technological solutions. "We're still early in the development of tools," he said. But better vaccines can take awhile to develop, Ballou said, and malaria is complex and the parasite that causes it has an "incredible ability to adapt to whatever pressures" on its survival we impose on it.

"What do you do in the short term?" Palca asked. "What should we be doing now? Where do the billions go first?"

Both Ballou and Phillips agreed that we have to use the tools we already have. "We have very effective control methods," Ballou said. Insecticide-treated bed nets, for example. The trouble is getting people to use the bed nets, which are hotter to sleep in than a non-netted bed. Ballou listed anti-malarial drugs and indoor residual spraying—where insecticide is sprayed on walls so that when mosquitoes land there to rest and digest after feeding, they absorb the insecticide—as other effective tools.

"Controlling malaria is like pushing on a balloon—unless you keep up the pressure it will rebound," Phillips said. "Once eliminated from a region, it is hard to sustain and active surveillance to look for new cases is necessary."

Palca asked whether the current economic crisis would affect financial support for solving the malaria epidemic. Ballou said the Gates Foundation would not be affected by the economic downturn.

Phillips' response was similarly optimistic for ExxonMobil's activities in the malaria control. "Our approach is to emphasize sustainability," he said. "While our company's profitability may vary over time, our commitment to our communities and programs is steadfast".

Benn Tannenbaum, associate program director for the AAAS Center for Science, Technology and Security Policy, said that Ballou and Phillips presented good examples of how to look at malaria in innovative ways. "It was a nice discussion of the life cycle of malaria and where you can apply pressure to the system," Tannenbaum said.

In its second year, the "Science and Society: Global Challenges" series was sponsored by AAAS's Center for Science, Technology and Security Policy, the Georgetown University Program on Science in the Public Interest and the Smithsonian's Lemelson Center for the Study of Invention and Innovation. Each of the four lectures in the series focuses on a different global challenge: climate, energy, national security policy and health.

Molly McElroy

17 November 2008