Wednesday, May 23, 2007

Blocking Bills to Honor Rachel Carson

Sunday is Rachel Carson's 100th birthday, and in honor of the occasion, Senator Ben Cardin (D-MD) planned to introduce a resolution to commemorate Carson and her work. However, Senator Tom Coburn (R-OK) has threatened to block the legislation. His office trotted out the familiar claim that Carson caused millions of deaths.

In a statement on his Web site yesterday, Coburn (R) confirmed that he is holding up the bill. In the statement, he blames Carson for using "junk science" to turn public opinion against chemicals, including DDT, that could prevent the spread of insect-borne diseases such as malaria, which is spread by mosquitoes.

Coburn, whose Web site says he is a doctor specializing in family medicine, obstetrics and allergies, said in the statement that 1 million to 2 million people die of malaria every year.

"Carson was the author of the now-debunked 'The Silent Spring,' " Coburn's statement reads. "This book was the catalyst in the deadly worldwide stigmatization against insecticides, especially DDT."
Coburn is also blocking a bill that would name a post office after Carson in her hometown.

DDT is not banned. Or, rather, it is banned only for agricultural uses, and only in countries that choose to ban it for such purposes. As I noted previously on this blog, use of indoor DDT spraying for malaria control has been approved by the WHO, with USAID following suit. DDT fell out of favor as an anti-malaria pesticide primarily because of reduced effectiveness, and not because of the agricultural ban. In fact, the reduced effectiveness of DDT for malaria control may be related to the massive amounts of the chemical used for agriculture. Rachel Carson herself warned against the development of resistance in malaria mosquitos:
These are important problems and must be met. No responsible person contends that insect-borne disease should be ignored. The question that has now urgently presented itself is whether it is either wise or responsible to attack the problem by methods that are rapidly making it worse. The world has heard much of the triumphant war against disease through the control of insect vectors of infection, but it has heard little of the other side of the story - the defeats, the short-lived triumphs that now strongly support the alarming view that the insect enemy has been made actually stronger by our efforts. Even worse, we may have destroyed our very means of fighting.

A distinguished Canadian entomologist, Dr A. W. A. Brown, was engaged by the World Health Organization to make a comprehensive survey of the resistance problem. In the resulting monograph, published in 1958, Dr Brown has this to say: Barely a decade after the introduction of the potent synthetic insecticides in public health programmes, the main technical problem is the development of resistance to them by the insects they formerly controlled. In publishing his monograph, the World Health Organization warned that the vigorous offensive now being pursued against arthropod-borne diseases such as malaria, typhus fever, and plague risks a serious setback unless this new problem can be rapidly mastered. [quoted here]
Rachel Carson should not be blamed for deaths from malaria.

The agricultural ban on DDT was implemented for good reason. As noted above, mosquitos developed resistance to DDT when they were exposed to sublethal doses through massive agricultural spraying. As a result, banning agricultural use may help keep DDT as a viable option for malaria control. In the United States, agricultural use led to severe declines in several species of birds, which suffered reproductive failures because of DDT and its by-products. DDT is also not as safe for humans as some make it out to be. It has been shown to affect the nervous system and reproductive functions, and has raised liver cancer rates in other mammals. Despite the thirty-year-old ban, DDT and its by-products persist in the environment, in birds, in the food supply, and in human breast milk.

Perhaps Coburn should take a turn at the DDT Ban Myth Bingo.

Deltoid, The World's Fair, and Gristmill have more.