Thursday, May 7, 2009

Back and Forth on DDT Again

What's missing from the latest news about the World Health Organization, DDT and malaria? Context! Context! Context! Namely, if DDT had been used from the time of its invention only for public health purposes--for indoor residential spraying against mosquitoes in areas hard-hit by malaria--it would probably never have developed its toxic reputation.

The fact that agricultural interests--particularly cotton farmers--adopted wholesale DDT spraying is what killed birds and poisoned entire ecological systems.

There is a special case to be made for judicious, environmentally-protective DDT spraying of residential homes--particularly in hard-hit African countries. South Africa has shown how to do this and still protect the environment. (I wrote about this in TIME Magazine five years ago. Please also note, it was the combination of DDT and treatment with an anti-malarial drug that turned the tide.)

The World Health Organization seemed to have acknowledged that point back in 2006.

Now comes word that they hope once again to achieve a total ban on DDT, thanks to pilot programs that have used other anti-mosquito pesticides and means in Mexico and Central America. Please note: malaria is much worse, much more prevalent in central and southern Africa so what works in Mexico may have little effect in malarial zones of Africa.

As for increased resistance of mosquitoes to DDT, the point is actually not to kill the mosquitoes but to keep them from biting. And DDT is actually a better mosquito repellent than anything else--exactly what you want, according to a 2007 study in Nature Medicine.Link

I suppose all public health programs have an element of politics but I find it very frustrating to read news reports that pretend that all decisions with respect to DDT are made solely on a scientific basis.

Related posts:
Can Malaria Be Eradicated?
Human Health Effects of DDT


Anonymous said...

DDT's repellant powers are not so great as DEET. DEET, while poisonous, is much safer than DDT.

DDT isn't a panacea. There is no use for which there isn't something that works better and is much less dangerous.

Since the hope to eradicate malaria seems to rest on improving health care and preventing bites with physical barriers, why not drop DDT now? Is there any study to suggest DDT can be used with complete safety? No. Is there any study yet to suggest that DDT can make a significant contribution to fighting malaria that no other substance can? No.

Why bother with DDT at all?


Ed Darrell

Christine Gorman said...

I agree DDT is not a panacea.

But there are times and places where it is appropriate. Wishing otherwise does not make it so.