Saturday, May 16, 2009
By Roger Bate
For two years the United Nations paid lip service to the truth that the insecticide DDT is a vital weapon against malaria but last week it abandoned science in favor of superstition, promoting dangerous and weaker methods against the disease that kills a million a year.
The World Health Organization (WHO) and the United Nations Environment Program announced on 5 May plans to reduce DDT use by 30% by 2014 and eliminate it around 2020. Meanwhile, they will test non-chemical malaria control in 40 countries in a huge human experiment on the poor.
In particular the UN wants to increase the programs of Central America and Mexico, which have relied on “pharmacosuppression”: uninfected people in high-risk places take the antimalarial drug chloroquine to suppress any future infection. In 2004, only 3,400 malaria cases were diagnosed in Mexico and 6,897 in Nicaragua but, although chloroquine has saved millions of lives as treatment, its extended prophylactic use is not safe for the heart: as scientists at the University of Colima in Mexico explained last year, chloroquine “can induce lethal ventricular arrhythmias." The UN also does not mention that the Central American policy cannot be used anyway in most other regions, including Africa, because of extensive resistance to chloroquine and high cost.
DDT, on the other hand, has saved millions of lives in the last century, with little to no environmental damage and no harm at all to human health. From the late 1940s until the early 1970s, spraying DDT was mainly responsible for eradicating malaria from North America and much of Europe. By 1970, an estimated one billion people were no longer threatened. In Southeast Asia, cases fell from a high of 110 million in 1950 to nearly zero by 1969.
The only problem was over-use, causing resistance to DDT in mosquitoes: the solution turned out to be minimal use, "residual spraying" on the inside walls of houses, which remains highly effective.
But by the 1980s aid agencies had lost interest in malaria control. When malaria re-emerged as a global priority in 1998, even residual spraying was off the table. Deaf to appeals from southern African public health experts who were successfully using DDT, aid groups opted to promote less controversial bed nets and antimalarial drugs.
Bed nets can save lives, especially when impregnated with insecticide, and are relatively cheap. But they must be used consistently, every night, all night: studies suggest most people do not do so. And when bed nets are accompanied by education campaigns, their unit cost often becomes more expensive than spraying. Most aid groups simply count distribution but rarely attempt to measure how many lives they save.
Recognizing this, and with malaria rising throughout the 1990s and 2000s, the 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.”
Still, even with this WHO endorsement, only a few countries, all helped by the US Government, such as Uganda and Tanzania, tried DDT. Most nations were reliant on government aid and charities like Doctors Without Borders and 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.
In its place, the UN promotes the inappropriate Central American pharmacosuppression model and other marginal trendy techniques, such as fish which eat mosquito larvae. This can work in very specific circumstances but, since many mosquito species can breed in tiny amounts of water, even in old tires or hoof prints, it is not much use. Window screens are useful but expensive and only work in houses where mosquitoes cannot enter through the eaves, thatch or brush walls, which many huts in Africa have.
Although there are some alternatives, after 65 years of use DDT is still a major, yet largely unfunded, part of the anti-malaria arsenal. A child dies of malaria every thirty seconds, mainly in Africa: more will now die for the UN’s political correctness.
Roger Bate is the founder of health research group Africa Fighting Malaria and the Legatum Fellow at the American Enterprise Institute, a think-tank in Washington, DC.