For two years the United Nations paid lip service to the truth that the insecticide DDT is a vital component of malaria control, but last week UN abandoned science in favor of superstition. The result is UN promotion of more dangerous and less efficient malaria control techniques.
On May 5th, the World Health Organization (WHO) and the United Nations Environment Program announced plans to reduce DDT use by 30% by 2014 and completely eliminate it by around 2020. In the mean time, the UN will roll out initiatives in 40 countries to test non-chemical methods of malaria control. In particular UN wants to scale up the programs of Central America, which have relied on "pharmacosuppression". Essentially, uninfected people in high risk locations are given the antimalarial drug chloroquine to suppress any future infection. In 2004, 3,400 malaria cases were diagnosed in Mexico, 6,897 in Nicaragua, and almost half a million in Brazil. But both Mexico and Nicaragua each distributed more anti-malaria pills (mostly chloroquine pills) than Brazil. Chloroquine is a wonderful drug at combating malaria and has saved millions of lives when used therapeutically, as in Brazil, but prophylactic use is not safe because it is quite toxic and has led to heart problems when used repeatedly. As scientists at the University of Colima in Mexico explained last year, chloroquine "can induce lethal ventricular arrhythmias."
Ironically, chloroquine is only slightly less toxic than DDT yet people have to eat chloroquine pills, they don't eat DDT. The UN does not mention this, or that the Central American policy cannot be used in most other regions because of extensive resistance to chloroquine and high cost. So even if pharmacosuppression were clinically appropriate, it couldn't be done in Africa anyway.
The UN's push for a "zero DDT world", ignores the millions of lives DDT has saved over the past century, with little to no adverse environmental impact and no harm to human health. From the late 1940s until the early 1970s, spraying DDT was the mainstay of anti-mosquito campaigns responsible for successfully eradicating malaria from North America and much of Europe. Thanks to DDT, by 1970, an estimated one billion people no longer lived in malaria-endemic areas; in Southeast Asia, cases fell from a high of 110 million in 1950 to nearly zero by 1969.
But by the 1980s aid agencies lost interest in funding malaria control. When malaria re-emerged as a global priority in 1998, even the most limited use of DDT--for indoor spraying, in tiny quantities--was off the table. Deaf to appeals from Southern African public health experts who were successfully using the chemical, aid groups opted to promote less controversial bed nets and antimalarial drugs.
Bed nets save lives, especially when impregnated with insecticides, and are relatively cheap. But they must be used consistently, every night, all night. Studies suggest most people do not routinely sleep under their nets--and when bed nets are accompanied by education campaigns, their per-unit cost often becomes more expensive than spraying ‑ with DDT. Most aid groups buy nets and simply count their distribution; they rarely attempt to measure how many lives they save.
Recognizing this, and with malaria rates rising throughout the 1990s and 2000s, WHO reversed its policy in 2006. "We must take a position based on the science and the data," Dr. Arata Kochi, Director of WHO's Global Malaria Programme announced in September 2006. "One of the best tools we have against malaria is indoor residual house spraying. Of the dozen insecticides WHO has approved as safe for house spraying, the most effective is DDT." Dr. Kochi wanted all the tools available to combat malaria--bed nets and insecticides like DDT.
Still, even with this WHO endorsement, only a few national governments, all helped by US Government, such as Uganda and Tanzania tried using DDT. Most nations were reliant on governmental donors and NGOs like Doctors Without Borders and more recently, Malaria No More, which favor net distribution. The only large donor that has even tried using DDT in Africa since the 1970s has been the US President's Malaria Initiative. So only a moderate increase in DDT use occurred, none funded by the UN. And then last year Dr Kochi was sidelined along with his pro-DDT policy. The result was that WHO, UN's premier health body, which had weakly championed DDT for less than two years, was back in step with the rest of UN agencies, notably UN Environment Programme, which continued to promote DDT's demise.
In its place UN promotes the highly dubious Central American pharmacosuppression project as well as other marginal trendy techniques, such as fish which eat mosquito larvae. This can work but only in very specific circumstances, and since many mosquito species can breed in tiny amounts of water--trapped in old tires or even hoof prints, it is easy to see why they are not widely deployable. Window screens are useful, but they are expensive and are only successful in houses where mosquitoes cannot enter under the eaves, through thatch, or even brush walls, which many huts in Africa have.
So while there are many alternatives to DDT, after 65 years of use, DDT is still a key, yet largely unfunded, part of the anti-malaria arsenal. The children of Africa pay the price for the UN's political correctness.
Roger Bate is the Legatum Fellow in Global Prosperity at AEI.