Advocate of DDT Says It Is Effective Against Malaria and Poses Little Health Risk

Thomas “Woody” Highsmith of Evans, Georgia is retired from the Georgia Department of Agriculture Entomology & Pesticides Division, was a Department of Defense pest control contractor in Afghanistan from 2006-2009, and is currently facilities pest controller at the Carl Vinson Veterans Medical Center in Dublin, Georgia. He responded to my letter DDT is No Solution to Malaria with a defense of DDT.

Chapter 7 in Merchants of Doubt by Naomi Oreskes and Eirk M. Conway succinctly reviews the criticisms of Rachel Carson and later decisions to restrict the use of DDT and other pesticides. They confirm the assertion I made in my letter that attacks on Rachel Carson and DDT restrictions are more about proposed regulation today than saving the food supply or preventing malaria deaths.

… [B]y 2007 DDT had been banned in the United States for more than thirty years. This horse was long out of the barn, so why try to reopen a thirty-year-old debate? Sometimes reopening an old debate can serve present purposes. In the 1950s, the tobacco industry realized that they could protect their product by casting doubt on the science and insisting the dangers of smoking were unproven. In the 1990s, they realized that if you could convince people that science in general was unreliable, then you didn’t have to argue the merits of any particular case, particularly one–like the defense of second-hand smoke-that had no scientific merit. In the demonizing of Rachel Carson, free marketeers realized that if you could convince people that an example of successful government regulation wasn’t, in fact, successful — that it was actually a mistake —  you could strengthen the argument against regulation in general. (p. 217)

Silent Spring was published in 1962, yet ten years passed and three national-level groups produced science assessments before President Richard Nixon’s Environmental Protection Agency (EPA) “banned the use of DDT in the United States. There was no rush to judgment against DDT: it took three presidencies to enact the ban.” (p. 221 )

Aside from the obvious response that the EPA’s ban of the use of DDT in the United States did not prevent its use elsewhere and thus is not responsible for continued mortality and morbidity from insect-borne diseases such as malaria, Oreskes and Conway summarize why DDT use would not have prevented this illnesses.

After DDT’s demonstrated successes in World War II, the United States and the World Health Assembly launched a Global Malaria Eradication Campaign (1955-1969). It was not based on large outdoor spraying campaigns — the principal target of Carson’s indictment — but primarily on indoor spraying of household walls and surfaces with DDT (and dieldrin). The U.S. Centers for Disease Control summarizes the results: “The campaign did not achieve its stated objective.” Endemic malaria was eliminated in developed nations, mainly in Europe and Australia, and sharply reduced in India and parts of Latin America, but the campaign failed in many less developed areas, especially sub-Saharan Africa. It was halted in 1969 — four years before the U.S. ban. … Malaria eradication failed in less developed nations because spraying alone didn’t work. Spraying along with good nutrition, reduction of insect breeding grounds, education, and health care did work … But the most important reason that eradication was only partially successful was that mosquitoes were developing resistance. In the United States, DDT use peaked in 1959 — thirteen years before the ban — because it was already starting to fail. (pp. 223-4)

One of the most prominent attackers of Rachel Carson, environmentalism and science was Dixy Lee Ray. Spraying of DDT in Sri Lanka reduced the number of annual cases of malaria from 2.8 million in 1948 to 17 in 1963. By 1968 and 1969, the numbers had risen to 1 million and 2.5 million, respectively. She blamed this on “the largely unsubstantiated charges against DDT in the United States.” Oreskes and Conway refute this assertion:

In 1968, malaria flared up again, and DDT couldn’t control it. Still, the Sri Lankans persisted, using even more DDT over larger areas at more frequent intervals. … So Sri Lanka didn’t stop using DDT because of what the United States did, or for any other reason. … [S}ince DDT had appeared to work at first, officials were reluctant to give it up, even as malaria became more resurgent. As a [World Health Organization] (WHO) committee concluded in 1976, “It is finally becoming acknowledged that resistance is probably the single biggest obstacle in the struggle against vector-borne disease and is mainly responsible for preventing successful malaria eradication in many countries [p. 7].” (pp. 230-1)

A later version of this WHO report reached the same conclusion, particularly in regard to malaria vectors (p. 8).

Regarding J. Gordon Edwards, whose article in the Journal of American Physicians and Surgeons Mr. Highsmith quotes, Oreskes and Conway write:

We met Steve Milloy in chapter 5, as he founded The Advancement of Sound Science Coalition on behalf of Philip Morris in 1993 to defend a product that really had caused millions of deaths. Soon thereafter, he began to spread the “millions of deaths” claim about DDT. According to his 1997 annual report, he began working with J. Gordon Edwards, an entomologist at San Jose State University, to help him publish an account of the DDT controversy.

Regarding the Journal of American Physicians and Surgeons, it is “associated with the Oregon Institute of Science and Medicine, who sponsored the anti-global warming petition. The journal, previously known as the Medical Sentinel, is the outlet of the Association of American Physicians and Surgeons, which among other things filed a suit on behalf of Rush Limbaugh when his medical record were seized as part of his prosecution on drug charges. The Sentinel published articles questioning the link between HIV and AIDS, including a commentary by Michael Fumento, the journalist we met in chapter 5 who was defending pesticides while accepting money from the Monsanto chemical corporation. … (Neither the Web of Science nor MEDLINE/PubMed lists the journal among its peer-reviewed scientific sources.)” (p. 245)

Oreskes and Conway document the financial contributions Philip Morris, the giant tobacco firm, made to many of the non-profits repeating the most outrageous claims regarding DDT. (pp. 233-5)

Merchants of Doubt is an excellent book which I highly recommend. I’ve omitted a lot of evidence from its Chapter 7 which further supports the EPA’s decision to restrict the use of pesticides, including DDT.

I hope that this settles the question I originally addressed, namely the potential of DDT spraying as a public health measure.

Below are additional links I’ve collected but decided not to include for the sake of brevity.

Updated 2015-November-10: Number 3 of Seven things worth knowing about mosquitoes

3. Mosquitoes have started to change their feeding patterns

Because of the strong focus on indoor strategies to fight malaria transmitting mosquitoes using bed nets and indoor spraying, genetic selection is resulting in some populations of these mosquitoes biting outdoors and earlier at night when people are not protected by bed nets. It means these mosquitoes are more difficult to reach with insecticides, just as is the case with Anopheles arabiensis.

Updated 2015-November-11: Ed Darrell, who blogs at Millard Fillmore‘s Bathtub, provides more information & writes better than I did here!

Also, there’s this:

Amir Attaran

J Gordon Edwards, Ph.D

Anti-DDT links

200+ reasons to ban DDT

Socioeconomic development as an intervention against malaria: a systematic review and meta-analysis (downloaded full-text at D:\academic\TransatlanticEncyclopedia\Sources\Malaria Socioeconomic Status.pdf)

DDT appears in whales’ ear wax

President’s Science Advisory Committee (PSAC): Pesticides report, 15 May 1963

Science and public policy: what’s proof got to do with it? by Naomi Oreskes, Environmental Science and Policy, October 2004


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