U.N. says DDT needed to halt the ravages of climate-spread malaria
Posted on May 9th, 2008By Nathanial Gronewold
Climatewire: U.N. Secretary-General Ban Ki-moon went on a public health tour yesterday that took him to the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta and to a dinner at the Carter Center at which he discussed global health issues. The tour is part of an effort to call on the U.S. government and the public to support his “Roll Back Malaria” campaign, a worldwide initiative launched two weeks ago that he hopes will finally put a serious dent in the deadly disease.
Last month, the World Health Organization (WHO) issued an alarm over the growing negative health implications of climate change. Singled out for particular scrutiny is its contention that climatic changes in Africa and Asia are contributing to the spread of vector diseases, especially malaria, as higher elevations become warmer and changing precipitation patterns move mosquitoes into previously uninfested areas.
Now WHO, the U.N. system at large and multiple health agencies are gearing up for the campaign Ban has called for, zeroing in on Africa. The aim is to cover all populations in those parts of Africa most affected, using anti-malarial tools such as mosquito repelling bed nets and providing better health care, in the hope of bringing the disease under control by the end of 2010.
But the heightened campaign against malaria, interpreted by some as not only an urgent public health need but also a necessary means to adapt populations to the consequences of climate change, is stirring new debate over the use of DDT, a dangerous carcinogen, in the battle.
After studying the matter for some time, in 2006 WHO came out in favor of using DDT to control the spread of malaria. That sent alarm bells ringing among environmentalists who fear such high-level approval will lead to widespread illegal use and abuse of DDT, reintroducing a chemical pollutant found to be especially harmful to human health.
“Indoor residual spraying is not the most effective way to necessarily combat malaria,” said Medha Chandra, an international campaigner with the Pesticide Action Network.
While the focus of attention in this new campaign is so far resting squarely on the urgent need to cover communities with health care and protective measures and save lives, expanded use of DDT through a technique known as residual indoor spraying threatens to once again divide the health and environmental communities on this issue.
U.N. officials say anti-malaria campaign could pay for itself quickly
Regardless of the controversy over DDT, no one doubts the seriousness of the malaria epidemic that continues to ravage much of Africa and stunt the region’s economic growth prospects.
Malaria is estimated to kill 1 million people in Africa each year, with women and children constituting the vast majority of those fatalities. Economists believe that the costs of the disease, through diverted resources and lost productivity, shave about 1.3 percent, or about $30 billion, off potential economic growth on the continent each year. One child dies every 30 seconds in Africa from the disease, according to WHO director Margaret Chan.
Yet the cost of responding pays for itself in the long run, activists say. Ray Chambers, the United Nations’ special representative for malaria, said that the secretary general’s campaign would require about $6 billion over the next three years, or $2 billion per year.
“That’s a return of 1,500 percent per year, and those of us in the financial community would make that investment every day,” Chambers said.
But more importantly, the potential number of lives that could be saved by simply ramping up efforts and techniques currently under way elsewhere is huge, said Chambers.
“We’ve seen great progress in countries like Ethiopia and Rwanda,” he said. “We’ve seen deaths of people drop by over 60 percent.”
But the Roll Back Malaria push will require the WHO, local government health agencies and aid organizations to pull out all the stops and use all methods proven effective. “We have to use all the tools we currently have to their greatest potential,” Chambers said.
Indoor spraying of DDT regarded as an essential ‘tool’
That includes indoor residual spraying, or applying DDT to cracks in the walls and ceilings inside homes to keep mosquitoes out of living quarters.
“I am putting forth a bold but achievable vision,” said Secretary-General Ki-moon last month at a special event at U.N. Headquarters in New York to launch the campaign. “The aim is to put a stop to malaria deaths by ensuring universal coverage by the end of 2010. This initiative will offer indoor residual spraying and bed nets treated with long-lasting insecticide to all people at risk, especially women and children in Africa.”
While supportive of the push against the disease, many activists are still wary of WHO’s support for using DDT. There are other, safer and more proven methods for combating the disease, they say.
“The way to combat malaria is, it’s a systems disease,” said Chandra. “You need to invest in health care in an overall systematic approach, and this should include environmental measures like better sanitation, better environmental control, use of larvacides, use of bed nets and medication … things like that which would not attack the vector from one single point but every different part of its lifecycle.”
But if indoor residual spraying has to be employed, DDT certainly is not the only option, Chandra insists. “There are other chemicals that are used in indoor residual spraying that are less toxic than DDT. And while we don’t endorse the use of chemicals per se, if one had to do indoor residual spraying, then those other chemicals are a better option than DDT,” she said.
A past study by the World Wildlife Fund supports the idea that not enough respect had been paid in past anti-malaria campaigns — which employed DDT on a widespread basis, most notably in the 1950s — to the harmful and long-lasting consequences of DDT use on human health.
WHO officials believe most of DDT’s problems can be avoided
“What has not been factored into the equation is the unacceptably high hazard DDT poses to global biodiversity and human health, especially since reasonable alternatives exist,” WWF says in the report.
WHO officials acknowledge that they will face some headwinds from the environmental establishment as they move forward with expanded indoor residual spraying.
“DDT has always been the kind of bugbear, obviously because it’s a persistent organic pollutant, so there’s lots of people who object to DDT being used,” said Greg Hartl, an officer with WHO at its headquarters in Geneva. “Certainly among the environmental lobby … it causes a lot of controversy.”
But WHO disputes notions that other methods or chemicals can be used in lieu of DDT. The global health agency acknowledges that DDT is very harmful to human health, especially with long-term exposure, and that the chemical poses a particular risk to children. But its officials insist that most of the negative health consequences can be avoided when it is carefully and safely applied. And any risk that DDT may pose is far outweighed by the carnage malaria is causing now.
“It’s mostly used in Africa, where the situation is so serious that other means of control are really failing,” said Carlos Corvalan of WHO’s regional office in Brazil. “Of course everyone would advocate for a more ecological approach to the control of malaria, but the question is, when you have children dying and when you have very clear regulations on how you could use DDT somewhat safely, I think the decision has been to go ahead with this spraying within the boundaries and limits of the regulations.”
Environmental groups fear ecological backlash
Nevertheless, opponents to indoor residual spraying fear that WHO and others are risking an even greater ecological backlash coming about as DDT use spreads more widely throughout Africa.
“The resistance issue is very relevant here, because mosquitoes develop resistance very fast,” said Chandra.
But others say such fears are overblown. A study by the U.S. Centers for Disease Control on DDT use in controlling malaria in South America suggests that mosquito resistance to the pesticide may not be as prevalent as many fear.
“Failure to maintain control over malaria most likely results from failures in the functions of interventions or from failures to make proper application of interventions,” said the authors of the CDC study. “Although DDT resistance is often posed as a reason for malaria control failure, resistance of vector populations to DDT is not widespread in South America.”
WHO says that the emergence of ever more resilient malaria viruses and mosquitoes is always a constant threat, one that they must keep on top of through vigilant monitoring and research into more effective insecticides and medicines. That will prove more important than ever now that climate change threatens to push the disease-bearing mosquitoes to new areas, they say.
“We need to continually push the research and development agenda,” WHO director Chan told participants at the launch of the organization’s latest initiative. “If we lose it by resistance, the world is heading for a big, big crisis.”
And ensuring that DDT is applied safely and effectively will no doubt prove another challenge as this latest push against malaria heats up and expands. But in the short run, organizers of the campaign are focused exclusively on generating the funds they will need and mobilizing governments and organizations to handle what is shaping up to become the most ambitious international public health drive since the eradication of polio.
“This is our moonshot,” said Jeffrey Sachs, director of the Earth Institute at Columbia University and a special adviser to the U.N. secretary-general. “The message has to go out today to every leader in Africa. This is for real.”