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WHO Says DDT needed to control malaria September 16, 2006

Posted by angryscientist in Bad Science, Uncategorized.

The World Health Organization is not about promoting health. DDT has been banned for many years in rich nations, but now WHO insists DDT should be sprayed inside houses in all countries where malaria is a problem.

This quote is in most of the news stories:

“One of the best tools we have against malaria is indoor residual house spraying,” said Dr. Arata Kochi, director of WHO’s malaria program.

“Of the dozen pesticides WHO has approved as safe for house spraying, the most effective is DDT.”

Here is another juicy quote, from CBC News:

Environmental groups that previously opposed DDT spraying such as Environmental Defense and the Sierra Club endorsed the plan, while stressing the need to search for alternatives.

As if there are no alternatives. Give me a break. Even WHO does not say there are no alternatives, just that DDT is the most effective. Often what seems the most effective way of dealing with a problem has consequences worse than the problem itself. Malaria can kill, but so can DDT, especially poverty stricken malnourished people. As a prime endocrine disruptor, DDT also has nasty effects on childhood development, but WHO has the nerve to say DDT presents no health risk when used properly. This meat ax approach brings to mind the old canard about destroying the village in order to save it.


1. angryscientist - March 20, 2007

Another meat ax approach is in the works, a mosquito engineered to resist malaria!

From the Times of London

Large numbers of GM mosquitoes would be released in areas where malaria is common, where they would interbreed with wild ones. Over several generations, resistance should spread through the mosquito population, so that fewer insects carry malaria. However, this approach would prove controversial with environmental groups, as it would involve supplanting a naturally occurring species with a genetically engineered variant.

Critics have argued that it is difficult to be certain of the effects of introducing new genes. Even the scientists involved accept that further research is needed before any GM insects could be introduced into the wild.

A further problem is that only a very small proportion of wild mosquitoes are exposed to malaria, and the transgenic insects did not have a competitive advantage when the parasite was not present. This would slow the rate at which they might have an impact on malaria transmission.

A different approach has been adopted by a British team, led by Andrea Cristiani, of Imperial College, London. His team has developed a GM mosquito in which the males have fluorescent testicles, allowing them to be easily identified and sterilised. The goal is to introduce large numbers of sterile males, which would mate with normal females, reducing the number of eggs laid, and thus of malaria mosquitoes. As the mosquitoes are sterile, they would not transmit transferred genes into wild populations.

I remember the fiasco in California when Gov. Jerry Brown tried to combat a Mediterranean fruit fly infestation with sterilized male flies that turned out not sterile. He was trying to avoid spraying cities with malathion, a laudable goal, but these high tech interventions have a habit of falling prey to Murphy’s law, whatever can go wrong, will.

2. angryscientist - May 4, 2007

Now WHO is saying it is committed to reducing reliance on DDT in malaria control! Make up your mind, WHO!

I found this courtesy of the Pesticide Action Network

WHO’s Dr. Neira addressed a large audience of government officials from around the world at a WHO/UNEP event in Dakar entitled “Reducing Reliance on DDT While Strengthening Malaria Control.” She affirmed that WHO’s goal is to reduce and eventually eliminate use of DDT, in accordance with the Stockholm Convention. She stressed that this has been the case since the Convention came into existence, and the WHO position on DDT has not changed.

Dr. Neira also confirmed the agency’s awareness of negative health effects associated with DDT, and that WHO is “very much concerned with health consequences [resulting from] use of DDT.” She said that “WHO is committed to making sure alternatives [to DDT] are soon available” and ensuring that member states comply and report on their use of DDT.

The workshop also heard from Dr. Enrique Loyola of the Pan American Health Organization about a malaria control project in Mexico that greatly reduced malaria without using DDT, achieving a 30% reduction at the village level, and a 50% reduction at the national level. Methods included public education, planting trees with mosquito repellent properties near homes and clearing away vegetation that might harbour mosquitoes, plastering homes with mosquito–repelling calcium hydroxide (lime), personal hygiene measures, cleaning canals and removing algae that serves as a mosquito refuge, and use of larvicides such as Bt (Bacillus thuringiensis). Mexico no longer uses DDT for vector control, and is now seeking to reduce use of other chemicals in vector management.

Representatives of the International POPs Elimination Network (IPEN) told WHO officials that when members of IPEN make similar statements about DDT, they are vilified and denounced as extremists in the press, often referencing previous WHO statements. They invited WHO to publicly state the agency’s concern about the health effects of DDT. They said that IPEN member organizations were anxious to work with WHO to help control malaria, but were being hampered by the perception that the WHO supports and defends increased use of DDT. This perception was created by coverage of a WHO position stated in September 2006, one very different from the WHO presentation in Dakar.

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