Winning the War on Malaria: Part One

Distribution of malaria by country.

Malaria is one of the greatest challenges facing developing nations. Each year, there are an estimated 300-500 million new cases of malaria, killing 1.2 million. It is a disease that disproportionately affects the poor in countries with tropical and sub-tropical climates, with most cases reported in Asia, Africa, and Latin America. The direct costs to individuals and governments for treating malaria have been estimated at $12 billion per year. If the indirect costs were considered, it would be many times greater due to lost wages, productivity, and economic growth.

Global spending to prevent and control malaria has amounted to $5.5 billion annually, a large amount given by official development assistance agencies in Europe and the U.S. Lately, however, there has been a growing role for Public-Private Partnerships such as The Global Fund to Fight AIDS, Tuberculosis, and Malaria and the Medicines for Malaria Venture. Philanthropic organizations such as the Bill and Melinda Gates Foundation and Exxon Mobil have made large contributions to malaria control efforts as well.

The giving has made significant progress in reducing the number of malaria cases. Interventions with bed nets, drugs, and vaccinations have all helped to reduce the number of malaria fatalities from a peak of 1.8 million in 2004. Yet much remains to be done to meet the Millennium Developmental Goals’ targeted reduction rates.

Prioritization of malaria prevention has led to a revival of Indoor Residual Spraying (IRS), the practice of spraying the interior walls of homes with insecticides. Long stigmatized because of negative environmental associations with the insecticides such as dichlorodiphenyltrichloroethane (DDT), IRS has begun to see a revival in popularity. Approximately 14 countries are currently using DDT in IRS applications, with several others making plans to reintroduce it. When used in combination with other prevention techniques, IRS has the potential to further reduce malarial infections.

Historical precedent suggests that when used on a broader scale, IRS can lead to substantial gains against malaria. A case in point is that of India during the 50s and 60s. During that time, USAID provided DDT to India, resulting in the reduction of the malaria burden from an estimated 100 million annual cases to about 100,000 in 1965—a 99.9% reduction rate. With IRS as the centerpiece of the campaign, malaria deaths plummeted from 800,000 a year to almost zero.

Indoor Residual Spraying in a Ethiopian home.

A strong correlation has been established between the usage of insecticides and malaria. Case studies in Madagascar, Venezuela, Belize, and South Africa have all confirmed increased malaria rates following national bans of DDT. After banning DDT for a short time in the 1990s, South Africa was forced to reintroduce it due to nonviable insecticide alternatives; in only one season after DDT was introduced, malarial cases declined by almost 70%. Similar success stories have happened for many other nations that have reintroduced DDT IRS.

Despite its remarkable track record in preventing malaria, DDT has been met with large amounts of resistance. Its manufacture and use have been banned in the U.S. since 1973, primarily because of Rachel Carson’s Silent Spring. The Stockholm Convention of 2001, signed by 150 countries, restricted the use of DDT and targeted it for eventual elimination. Recently, the United Nations Environment Program has determined that the date for elimination is 2020 and has begun a campaign to pressure countries to reduce DDT usage.

Granted, there are insecticide alternatives to DDT, but none are quite the same. DDT has a unique advantage over substitutes because it actually repels mosquitoes rather than killing them, preventing them from entering households and delaying the development of resistance. Of all the insecticides recommended by the WHO, DDT is the longest lasting and most cost-effective choice. For low-income countries with constrained budgets, DDT remains one of the most reliable weapons in the fight against malaria. As Guyanese Minister of Health Leslie Ramsammy, M.D., pointed out:

DDT is the most effective and affordable chemical we have to control malaria. . . . [T]he global response to the burgeoning malaria rates in the world should allow for DDT residual spraying.

Many of the more developed countries have begun to acknowledge the importance of DDT IRS. USAID has seen a complete reversal in its policy; two decades ago, the agency ordered some countries to completely ban DDT or lose foreign aid. Today, USAID supports DDT usage with IRS, providing over $20 million of support a year for African countries. The EU has lifted threats of trade obstruction against countries that have trace amounts of DDT in their agricultural products, a concession that has allowed countries to reintroduce DDT without fears of lost trade. These circumstances reveal that, to some extent, nations are becoming grudgingly cognizant of the fact that DDT is here to stay in the near future. Used responsibly, DDT has proven its potential to prevent unnecessary illnesses and save countless lives.


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