Gary Becker and Richard Posner have written a pair of posts about DDT and there is much wrong with what they have written.
The world Trade Organization (WTO) declared in 1998 a “war on malaria” that aimed to cut malaria deaths in half by 2010. Instead, deaths from malaria have been increasing, not falling. The reason for the failure of this malaria war is mainly that in the name of environmentalism, the WTO and other international organizations rejected the use of an effective technique, namely spraying DDT on the walls of homes in malaria-infected areas.
It was the World Health Organization (WHO), not the WTO. And far from rejecting the use of DDT in that period, the WHO endorsed it.
What is especially disheartening about the huge number of deaths from malaria, and a fact that sharply distinguishes malaria from Aids, is that malaria deaths could be greatly reduced in a cheap way without requiring any fundamental changes in behavior, A small amount of DDT sprayed on the walls of homes in vulnerable malaria regions is highly effective in deterring malaria-bearing mosquitoes from entering these homes.
As is spraying other insecticides or providing the residents with insecticide-treated nets. The problem is funds to pay for this and infrastructure to deliver it.
Finally recognizing this, a couple of weeks ago the WTO relaxed its support of the ban on DDT, and instead supported spraying of DDT on house walls in malaria-ridden areas.
This decision is likely to influence the position on DDT spraying of the World Bank, UDAID, and other relevant organizations.
In any case, by the end of 1972, DDT’s use in the United States was effectively banned. That ban soon became common in all rich countries, and in most poor countries too, as they responded to pressure from international organizations and Western governments.
The agricultural use of DDT in the US was banned in 1972. Use in public health was not. The Stockholm treaty on Persistent Organic Pollutants permits the use of DDT against malaria. The ban on the agricultural use of DDT has undoubtedly saved lives by slowing the spread of resistance.
One unintended consequence of the DDT ban was a devastating comeback by malaria and some other diseases after they had been in retreat.
As already noted, DDT was not banned. The main causes of the resurgence of malaria was the evolution of resistance to DDT and anti-malaria drugs.
The USAID has been a strong advocate of mosquito bed nets as an alternative to DDT. Mosquitoes operate mainly from dusk until dawn, so netting over beds can be effective if used persistently and correctly. Unfortunately, in many African countries bed nets are not readily available, and they are often not used to protect children since poor families may only have one or two nets. Moreover, families frequently do not bother to use these nets during some of the hours when mosquitoes are still active. So while bed nets could be a useful part of an overall strategy against malaria, they are not a good substitute for DDT.
Yes, bed nets don’t work if they are not available, but money spent on DDT spraying could instead be used for buying nets. The new long lasting nets appear to be more cost effective than DDT in the long term. And yes, bed nets don’t work if people don’t use them. But neither does DDT if they refuse to allow spraying or re-plaster their walls.
The ban on using DDT in houses to fight malaria is an example of environmentalism that lost all sense of proportion. As has happened with nuclear power and in other environmental situations, exaggerated claims about negative environmental effects of DDT on humans were publicized, and these claims were further exaggerated after being picked up by the media and politicians.
What has really happened is that exaggerated claims about negative effects of a non-existent DDT ban were publicized, and these claims were further exaggerated after being picked up by the media and politicians.
As a result of the hysteria against the use of DDT for any purpose, millions of lives were lost unnecessarily during the past several decades to malaria and some other insect-borne diseases. These deaths occurred only, I repeat only, because of international pressure on African and other poor countries not to use DDT and certain other pesticides in fighting malaria and other diseases caused by insect bites.
This is completely untrue. It is a right-wing fantasy and is grossly irresponsible for Becker to report it as fact. DDT has not been banned and it is not a magic bullet against malaria.
Richard Posner also has a post. He writes:
The Stockholm Convention on Persistent Organic Pollutants (2001) bans DDT but with an exception for its use against malaria, and the puzzle is why the exception is so rarely invoked, South Africa being a notable exception. An even greater puzzle is why the Bill and Melinda Gates Foundation, which is the world’s largest foundation and has made the eradication of malaria a priority, is spending hundreds of millions of dollars searching for a vaccine against malaria but nothing (as far as I know) to encourage indoor spraying with DDT.
Here’s the solution to the puzzle: Gates is a smart guy and has studied the problem more carefully than Posner. They had a massive program that tried to eradicate malaria with DDT spraying in the 60s and it failed. DDT is a useful tool against malaria and it is being used for that, but it won’t eradicate malaria. Gates is right to fund research into a vaccine and the development of new drugs and insecticides. (We desperately need new drugs and insecticides because the parasites and mosquitoes keep evolving resistance to the ones we have.)