How bad science opened door for malaria

Richard Tren & Donald Roberts | 21 Apr 2010
USA Today
Since it was first observed 40 years ago, Earth Day has grown from a handful of campus rallies into a global celebration of the environment and has raised ecological awareness around the world.

Unfortunately, the politics surrounding Earth Day have also done long-term harm, damaging our ability to fight deadly diseases today.

Back in the 1940s, scientists realized that the chemical dichlorodiphenyltrichloroethane, or DDT, could stop epidemics of insect-borne diseases such as typhus. Its lifesaving potential was considered such a boon to mankind that the scientist who discovered it, Paul Mueller, won the Nobel Prize. The chemical would soon surpass all expectations in controlling malaria around the world and go on to save millions of lives.

It was so effective that it eradicated the disease entirely in Europe, the U.S. and some island nations such as Taiwan. In the West, Malaria was defeated as an endemic disease more than 50 years ago. Now, though, it's a re-emergent disease of the poor, ravaging populations in South America, Asia and across sub-Saharan Africa. Spread by mosquitoes, malaria kills almost 1 million people a year and inflicts suffering on hundreds of millions more. But it didn't have to be this way.

Early environmentalists made pesticides one of their chief bugaboos. Rachel Carson, who helped launch the modern environmental movement, was among them.

In her now-famous 1962 book Silent Spring, she argued that DDT, when sprayed on a Michigan campus to halt the spread of Dutch elm disease, would spread far and wide and harm robins' ability to reproduce.

Carson was no doubt well-intentioned, but it turns out that she was flat out wrong about the effects of DDT. It didn't spread the way she thought it did, and no studies have ever been able to show that environmental exposure to DDT — even in large quantities — harms human health. It is less dangerous to humans than any number of natural chemicals, including some vitamins and medicines that we consume without a second thought. And when used in small quantities in malaria control, DDT protects people from deadly mosquitoes.

The public-health benefits it confers far exceed any of the unproven, theoretical risks.

A disease's comeback

All this is now widely known. But environmentalists' early crusades against pesticides have since taken on a global momentum of their own. Carson's anti-pesticide stance was taken up by many ecologists and led to the decision by the U.S. Environmental Protection Agency to ban DDT. By then, malaria had been eradicated in the USA, but it was still a scourge across much of the world. Nevertheless, international aid donors and health organizations began to abandon DDT.

In 1997, just as poor countries were suffering from a global pandemic of dengue fever and re-emerging malaria, the World Health Organization's policy-setting body adopted a resolution calling on all countries to reduce the use of insecticides for disease control. DDT was specifically identified as one that should be phased out.

Just 10 years later, the European Union took up the campaign. And in January of 2009, the European Parliament approved new rules to ban certain chemicals used in common pesticides. The new regulations created a great deal of uncertainty, and the implications are still not fully clear.

The harm that could come out of this is very real. Reckless rulemaking scares away would-be producers, even before a ban goes into effect. As we know from DDT's history, with fewer manufacturers in the marketplace, prices go up, making the chemical harder and harder to obtain.

As a result of the EU process, over the past few years, around 75% of the pesticides used in farming in Europe have disappeared from the market.

Trade worries, too

Bans also have other unintended consequences. For instance, some developing countries have stopped using DDT not because it wouldn't work in malaria control, but for fear that their agricultural exports would not be allowed into Europe if tiny and inconsequential residues were found on produce.

Meanwhile, malaria continues its deadly scourge, with no realistic alternative to fighting it on the scale that DDT can achieve.

The lesson is that we wouldn't have the crisis we do today if we hadn't put feel-good politics ahead of solid science decades ago. Thursday, the citizens of more than 180 countries will celebrate their commitment to the environment on Earth Day. This year, let's commit to putting science first. The consequences of not doing so last a very long time.