[ RadSafe ] DDT - needed now, but opposed by nuclear energy opponents

[howard long]

Like nuclear power, DDT use has been unscientifically castigated.

On Radsafe last month, DDT was claimed to have resistant plasmodia malaria

and other problems. These are put in perspective by these observations about its current use.

 

Howard Long

 
By Roger Bate, Richard TrenPosted: Wednesday, November 2, 2005ARTICLESCEI's On Point   Publication Date: November 1, 2005
The President's decision in June to spend an additional $1.2 billion over five years to halve the cases of malaria around the world was very welcome. Sadly, this noble gesture may be worth less than it should be, due to excessive reliance on bad advice and continued trust in an agency with a poor record on malaria control. 

It is the current fashion in international public health to attempt malaria control with insecticide-treated bednets. However, the U.S. Agency for International Development (USAID), which has been put in charge of the project, buys very few nets. In the recent past, while USAID has spent over $400 million on malaria control, analysis of the 2004 budget shows less than 10 percent of this was spent on actual commodities that save lives. USAID considers that its area of expertise is to provide technical assistance and this is consistent with why 81 percent of its 2004 budget never left the United States. While USAID advises people to sleep under bednets and doctors to buy drugs, it regards the provision of these essentials to be somebody else's job. USAID is reticent about publishing data on its projects, but in the few cases that have been detailed it was shown that, while this advice had been dispensed, neither bednets nor drugs were available. [1] 

Net Distribution is Not Disease Prevention 

Nevertheless, USAID touts its policy as a success and hopes to apply the model in Angola . According to its own reports: “[T]he distribution of free ITNs [insecticide treated nets] to mothers at the time they bring their children for immunizations has been very successful in both Togo and Zambia .” Ninety percent of mothers went away with bednets. But distribution is not protection; unfortunately USAID considers distribution a successful end-point. This is a fatally flawed assumption for several reasons. [2] [3] 

In the rural areas, after six months, only 72 percent of households had even bothered to hang up the nets. iv Donald Roberts, Professor of Tropical Diseases at the Uniformed Services University of the Health Sciences, analyzed USAID's papers for Africa Fighting Malaria--the organization that we head--and said that: “A review of data on use of insecticide treated nets in Zambia and Togo show that even when nets are provided free of charge, less than 56 percent of children possessing nets actually sleep under them. Net usage in urban areas is considerably less than the 56 percent usage in rural areas.” [3][4]

Only one net per household is distributed. Since children under five are at greatest risk of death, the youngest child is often allowed the protection, but what if there are several children under five in the house? [4] What about other family members? Many malaria l mosquitoes enter houses at sunset and feed most aggressively in the early hours of darkness, so unless a child is actually in bed under the net at nightfall he is at risk. If the protected child cannot sleep and wants to get into bed with Mom and Dad, stay up late, or get up early he is at risk. 

Furthermore, the insecticide--usually synthetic pyrethroids--in the net wears off after several months and, unless USAID is planning to buy long lasting insecticide nets, the net has to be taken for re-treatment. It is unclear from the reports from Zambia and Togo how many nets were brought back for re-treatment. Additionally, nets can be torn easily and subsequently offer very little protection. USAID cannot claim success in net distribution when it doesn't even know if the nets have been re-treated. 

None of these problems were measured in USAID-backed reports to estimate real efficacy, and, far more importantly, there was no effort to measure impact on morbidity or mortality from malaria. 

The Solution: Indoor Residual Spraying

Fortunately, there are highly effective alternatives. Several southern African states have initiated their own programs using a proven prevention method along with new treatment drugs to successfully control malaria . The only problem with this method is that it is politically unpopular in the developed world, and, most dismaying, it is shunned on environmental grounds that have no relationship to usage in malaria control. 

The best method of protection against malaria, in use for 50 years, is indoor residual spraying (IRS), which consists simply of spraying insecticide on the interior walls of houses. And the most effective, safest, cheapest, longest-lasting insecticide for this job is DDT--it crucially deters mosquitoes from entering a building where it has been sprayed. DDT eradicated malaria from the U.S. and Europe and its careful use led to dramatic declines in many other parts of the world. But over the last four decades environmental activists have persuaded public health professionals against using insecticide sprays, especially DDT. 

Where this dubious advice has been followed, malaria rates have risen proportionately to the reduction in spraying. But fortunately, those countries that did not have to rely on foreign funding for malaria protection--and could therefore afford to make their own public health decisions--went back to using DDT. A private initiative by a mining company in Zambia, covering over 360,000 of its workers, their families, and surrounding villages, reduced malaria incidence by 50 percent in just one year. [5] After South Africa suffered its worst ever malaria outbreak, it decided to risk Western displeasure and revert to the old methods. In one year, incidence of malaria was reduced by 80 percent. [6] Uganda is currently considering a return to DDT but is being threatened by the European Union (EU) with sanctions against agricultural products. The EU claims that DDT bought for public health protection could be corruptly sold to farmers and that residues would end up in produce.