EVENTS

Date:	Tuesday, December 2, 2003
Time:	2:00 PM -- 4:30 PM
Location:	Wohlstetter Conference Center, Twelfth Floor, AEI 1150 Seventeenth Street, N.W., Washington, D.C. 20036

December 2003
Tackling Malaria: The Role of DDT and New Drugs

Malaria kills between one and three million people each year, most of them children in sub-Saharan Africa. The disease's lasting effects on survivors reduce GDP by 1 percent every year, and economic development lags as a result. Malaria continues to pose problems, notwithstanding decades of work by U.S. Agency for International Development and international organizations. Working toward a solution is possible, however, even in the short run. A panel of experts focused on the controversial role of DDT in malaria prevention and the problems of developing and using drug treatments for malaria at an AEI conference on December 2, 2003.

Jennifer Zambone
Africa Fighting Malaria

Malaria was a major public health threat in the United States in the late nineteenth century, but the development of the pesticide DDT in 1938 achieved its total eradication. It was first implemented in 1944 by the U.S. military in Naples, Italy, where in just three weeks, the number of new cases dropped from 305 to 155. Soon after, the World Health Organization (WHO) launched a global malaria eradication campaign founded on the spraying of DDT that effectively squashed malaria in ten countries. In 1946, Sri Lanka housed three million cases of malaria. A decade of DDT use lowered its incidence to seven thousand, and by 1964, Sri Lanka had only twenty-nine cases of malaria. India also slashed its incidence from 75 million to fifty thousand by 1961, but the DDT campaign eventually failed because of poor execution, weak compliance, and reliance on a single pesticide. Moreover, the imposition of a uniform DDT strategy fatally overlooked the practical challenges of implementation in the widely different countries battling malaria.

Despite its promise in eradicating malaria, DDT came under fire for threatening wildlife and the environment, most notably in Rachel Carson's Silent Spring. Pressured by claims that DDT was also toxic to humans, the United States banned its use in 1972. While DDT is a known carcinogen to rodents, no body of evidence links it to cancer in humans. In fact, many foods regularly pose a higher risk to us.

Banning our greatest tool with which to combat malaria is dangerous. Every thirty seconds a child under five succumbs to the disease. Its toll can also be felt more broadly; the worst afflicted countries experience 1.3 percent lower economic growth than comparable non-malarious countries due to the disease alone. Indoor residual spraying (IRS) of the inside walls of homes effectively repels the mosquitoes that transmit malaria. Because DDT is so potent, IRS requires only a very small amount of DDT to work. In fact, a stock of DDT that would treat one thousand acres of cotton fields is enough to protect all of Guyana. At the 1994 Stockholm Convention on Persistent Organic Pollutants (POPs), the WHO tried to ban DDT and failed. Still, pressure to eliminate the pesticide's use has prompted relief organizations such as the Roll Back Malaria (RBM) partnership to employ new and often less effective strategies. RBM, an alliance between the United Nations Children's Fund (UNICEF), the United Nations Development Program (UNDP), the World Bank, and the WHO, uses primarily insecticide treated bednets (ITNs) to control malaria and not IRS. Reliance on this tactic is inadequate and threatens the lives of millions.

Mary Ettling
USAID

Chloroquine (CQ) was an effective therapy to prevent and treat malaria for forty years until resistance to it developed in Southeast Asia and the Amazon basin in the 1950s. Today its efficacy has also faded in tropical Africa, the region worst affected by the disease. CQ is easy to administer and familiar to the people who need it most but is therapeutically useless.

To effectively combat malaria, we must develop new drugs and viable strategies to deploy them. One promising therapy is rectal artesunate, a substitute for oral medications that are difficult to administer. The drug pipeline for malaria treatments will be extremely rich in the next five years, particularly for the artemisinin-based combination therapies (ACTs) under development. Several million artesunate treatments are already available, and manufacturers have the capacity to increase production. As we continue to invest in these new therapies, prequalification standards must be heightened to rigorously screen out growing numbers of counterfeit pills.

Malaria control rests also on sound treatment delivery systems. Deployment strategies must make use of tactics known to work, ranging from blister packs to community partnerships. Bolstering patient compliance in completing treatment is a major challenge, as the expense of the therapy often compels patients to stop taking their medicines when they feel better but before the dose is complete. This of course is not only ineffective but also dangerous for breeding resistance to the drug. Any successful reform of delivery systems must involve pharmaceutical companies, providers, patients, and caretakers.

Roger Bate
AEI

South Africa's experience with malaria reflects both successes and failures in eradication efforts. Ninety percent of malaria cases in South Africa are caused by the most dangerous species. In the 1980s, vector control interventions that employed DDT reduced the epidemic to a few thousand cases and only one hundred deaths per year. However, following a decision in 1996 to abandon the use of DDT, malaria incidence climbed again to one hundred thousand cases. The epidemic surged largely due to the influx of a new mosquito species that was highly resistant to the insecticides being used to destroy the malaria vectors. Where insecticides had failed, DDT remained effective as a repellant. To contain the malaria outbreak, South Africa launched a campaign that powerfully partnered the oldest preventive measures with the most innovative treatments. It resumed residual spraying with DDT and deployed the newest drugs to patients. In fifteen months, the incidence of malaria fell by 75 percent.

The Stockholm convention aimed to ban the use of chemicals, including DDT, for the risks they pose to human health and the environment. However, the political momentum driving these concerns comes from countries that no longer need these chemicals and at the expense of nations that rely on them in public health emergencies. These pressures have achieved a shift in malaria eradication efforts from IRS to insecticide treated bednets. Interventions such as ITNs are attractive to aid agencies because they can be used in various health campaigns-to combat not only malaria but also a host of water-borne illnesses, for example. Despite achieving worse outcomes, these strategies have garnered more political support and have become the foundation of antimalaria programs in much of the world.

Because so many national initiatives look to the WHO for guidance, it is imperative that this preeminent health body acknowledge the value of IRS. Much of the technical literature available today simply ignores this essential tool. Aid agencies have been generally unwilling to fund the use of DDT, confining its use to those countries that can themselves afford it. On a continent as impoverished as is Africa, this condition is grossly unjust. Though DDT has not been explicitly banned, onerous regulation of its storage and use have further made IRS prohibitively expensive. These restrictions must be lifted so that antimalaria efforts can make use of all available control methods. 

Amir Attaran
Royal Institute of International Affairs

Malaria is the second most prevalent disease in developing countries and takes the lives of enough children to fill seven Boeing 747 airplanes every day. Much of Africa's poverty can be attributed to the disease because its victims are typically unable to work. To eradicate this crippling disease, we must employ technologies that address both treatment and prevention.

Despite heightened efforts to combat malaria such as the Roll Back Malaria campaign launched in 1998, malaria prevalence is in fact increasing. It has been effectively controlled where we have genuinely committed to do so. The United States completely eradicated the disease in the nineteenth century, and South Africa contained its epidemic until drug resistance and environmental concerns about DDT removed the chemical from its eradication program. In the late 1990s, South Africa employed all the wrong medicines and used no insecticides, and malaria incidence and morbidity rose dramatically. In Kwazulu-Natal, one of the worst afflicted regions in the country, malaria took 350 lives in 2000. After resuming DDT spraying and treatment with ACTs, the province has had only one malaria death this year.

Despite several successes in malaria eradication, the disease continues to ravage parts of the globe. Control efforts are failing in part because ideology is defeating science and displacing the most effective vector control tool we have available, DDT, from antimalaria strategies. A second obstacle to eradicating malaria is the stinginess of aid donors and misuse of funds that they do spend. Malaria-stricken countries cannot beat the epidemics themselves, and the aid agencies on which they rely are doing too little. USAID's malaria budget, $65 million in 2002, is grossly insufficient to control this devastating epidemic. Worse still, aid groups are investing more in medicines proven not to work than on those that do. The Roll Back Malaria partnership generally buys chloroquine to treat malaria, but CQ has as high a clinical failure rate as 79 percent. As growing resistance to CQ renders the therapy useless, malaria programs must turn to artemisinin-based combination therapy (ACT) such as Coartem. ACT has treated the disease successfully throughout Africa, but aid agencies refuse to make it the treatment standard because it costs ten times as much as CQ. The Global Fund spends $16.1 million on ACT but far more on CQ and SP, $27.7 and $10.8 million respectively. Technical advisors' endorsement of a therapy with demonstrated ineffectiveness is negligent and verges on medical malpractice. It is a fundamental violation of human rights. Other technical advice offered by aid agencies is often not even competent. A few years ago, a joint World Bank-WHO malaria initiative posted an article on curing malaria with common salt on its website. Recommendations like these are not only tremendously irresponsible but also life threatening.

Larry Barat
World Bank

A fundamental hurdle to eliminating malaria across the globe is that we are not dealing with a single brand of the disease. The vector mosquitoes are different, and the intensity of transmission can vary widely, so our control strategies should as well. In Thailand, eradication efforts were aided by cutting the trees where malarial mosquitoes bred, but in Venezuela, mosquitoes dwell in water pools, and in tropical Africa they breed in cattle hoof prints filled with rainwater. IRS is not necessarily appropriate everywhere, but the World Bank does fund IRS programs in Eritrea, Madagascar, Mexico, and India. IRS's success rests largely on the available infrastructure. The only viable strategy to eradicate malaria is a combination approach that employs cost-effective, deliverable tools. We must address the weak health infrastructures and insufficient human resources that often make impossible the deployment of available technologies.

The World Bank recently convened a group of experts to advise the Roll Back Malaria partnership. First among their recommendations is a better forecast of the future demand for antimalarial therapies to encourage their development. Countries must in turn commit to manufacturers that they will buy whatever supply of ACTs are produced. These drugs will become increasingly affordable as increased production breeds competition among manufacturers and as countries pool their purchasing power. Prequalification mechanisms must be strengthened to assure the quality of the medicines, particularly as counterfeits and substandard products increasingly infiltrate the market. Antimalaria efforts must also make use of people on the ground to ensure that treatments are effectively delivered. To facilitate this, aid programs should contract out to private groups and nongovernmental organizations in those countries.

The World Bank and USAID's role in eradicating malaria is to support the programs in individual developing countries. Our organizations do not dictate the strategies; we respond to country needs. Consequently, we generally do not endorse or directly procure the drugs used in national malaria control campaigns.

AEI research assistant Ximena Pinell prepared this summary.