Malaria affects people in many countries, including many African and Asian countries, and countries of the Americas as far north as Mexico. DDT has been an effective tool in fighting malaria, but at a high cost to the environment and human health.

As mosquitoes have developed resistance to DDT and alternatives have become available, the use of DDT has been greatly restricted. A global ban has not been implemented, however, as its particular properties make it useful in certain very restricted settings where local strains of mosquito are susceptible, and where dispersion in the environment can be minimized. Environmental groups, notably the WWF,W are lobbying for effective alternatives to DDT to be developed and implemented, allowing it to be eventually eliminated.

History[edit | edit source]

DDT (dichlorodiphenyltrichloroethane) is a synthetic pesticide with a controversial history.

DDT's insecticidal properties were discovered in 1939, and it was used in the second half of World War II to control the insect-borne diseases, malaria and typhus. This led to a Nobel Prize in Physiology or MedicineW in 1948.[1] After the war, DDT was used as an agricultural insecticide, and its production and use skyrocketed.[2]

Bans and restrictions on DDT use[edit | edit source]

In 1962, Silent Spring by American biologist Rachel Carson was published, describing the environmental impacts of the indiscriminate spraying of DDT in the US and questioned the logic of releasing large amounts of chemicals into the environment without fully understanding their effects on ecology or human health. The book suggested that DDT and other pesticides may cause cancer and that their agricultural use was a threat to wildlife, particularly birds. Its publication was one of the signature events in the birth of the environmental movement, and resulted in a large public outcry that eventually led to DDT being banned in the US in 1972. DDT was subsequently banned for agricultural use worldwide under the Stockholm Convention, but its limited use in disease vector control continues to this day and remains controversial.[3]

Along with the passage of the Endangered Species Act, the US ban on DDT is cited by scientists as a major factor in the comeback of the bald eagle, the national bird of the United States,[4] from near-extinction in the contiguous US.[5]

Rachel Carson endorsed limited use of insecticide when needed - noting that limited rather than wasteful use would reduce problems of resistance.[6]

Production and use statistics[edit | edit source]

From 1950 to 1980, when DDT was extensively used in agriculture—more than 40,000 tonnes were used each year worldwide[7]—and it has been estimated that a total of 1.8 million tonnes of DDT have been produced globally since the 1940s.[8] Today, 4-5,000 tonnes of DDT are used each year for the control of malaria and visceral leishmaniasis, with India being the largest consumer. India, China, and North Korea are the only countries still producing and exporting it, and production is reportedly on the rise.[9]

The benefits of DDT[edit | edit source]

There has been lobbying to prevent a global ban on DDT,W largely arguing for the importance of its role in preventing malaria.

DDT is associated in the public mind with harm to ecosystems, and it has mostly been replaced with other pesticides with less persistence in the environment. However it remains effective in specific settings where other pesticides are not.

Malaria[edit | edit source]

India, Brazil and Mexico, where 69% of all reported cases of malaria occur (Mosq Control Assoc, 1998). Malaria afflicts hundreds of millions of people and causes millions of human deaths each year. Swiss scientist Paul Muller was awarded the 1948 Nobel Prize in Physiology or Medicine for discovering (1939) DDT's insecticidal properties.

DDT kills mosquitoes. Malaria is transmitted to humans via mosquito bites. According to U.N. estimates, malaria kills one child every 30 seconds and more than a million people each year.[1]

Appropriate use[edit | edit source]

DDT is best used on surfaces, especially indoors, as a weapon against the resting mosquito. It is:

  • Potent - just two grams of DDT per square meter of wall surface is more than enough to kill a mosquito within its usual one-hour resting period.
  • Inexpensive.Template:Detail
  • Easily stored and transported[verification needed]
  • Relatively safe for the person doing the spraying.[verification needed]
  • Long lasting - it remains effective for many, many months.[verification needed]

Inappropriate use includes spraying into the environment, where its long-lasting nature becomes a harmful property.

The environmental impact[edit | edit source]

DDT is associated in the public mind with harm to ecosystems, and it has mostly been replaced with other pesticides with less persistence in the environment.

But the environmentalist will have a hard time thinking of the condition of many species if the 1972 U.S. ban of DDT would not have been successful.[10] The most important thing at this point will be an in-depth study on whether it would be beneficial for countries with the malaria epidemic to use DDT as a preventative measure. They will also have to keep in mind how DDT will impact not only the health of humans, but the habitats of animals and other wildlife that may be negatively affected by the insecticide. For species that rely on insects for food, using DDT could ruin a population even if it is benefiting another.

From an environmental standpoint, it would sound absolutely crazy to be using a toxic insecticide to aide in an epidemic like malaria.

Using DDT to stop malaria in African countries[edit | edit source]

The African American Environmentalist Association believes that DDT (Dichloro-diphenyl-trichloroethane) insecticide should be used to prevent deaths from malaria in African countries. DDT is an organochlorine pesticide that has been used as an insecticide in agriculture and to combat insect vectors of diseases such as malaria and typhus. Because of its effectiveness at killing insects with few acute effects on humans, DDT had been a mainstay to fight malaria, a parasitic disease that is a growing health threat in Africa and other parts of the world.

Controversy[edit | edit source]

Controversy has been fanned by claims of millions of deaths resulting from a ban in the use of DDT. This is a simplistic and inaccurate picture of what has actually happened - for a start, DDT has never been completely banned.

WWF's call for an eventual ban[edit | edit source]

There is no longer a question about whether DDT should be banned, only how soon it can happen while still ensuring developing countries access to safe, affordable alternative malaria controls
— Clifton Curtis, director of the WWF Global Toxics Initiative, Group calls for worldwide DDT ban, 1999, CNN

WWF initially called for a global phaseout and eventual ban on DDT production and use by the year 2007, together with financial and technical assistance to the developing world. The 2007 deadline was intended as a motivational tool to encourage the necessary financial and technical assistance. The proposal of a 2007 deadline drew considerable public attention to the scope of the world's malaria problem and the need to implement alternatives to DDT.

However, it also raised fears that DDT would be phased out without sufficient guarantees of protection of public health from malaria. To allay these fears, WWF has set aside discussion of the 2007 deadline, while retaining its commitment to eliminating DDT. Both the UNEP and WHO recognize that such elimination can be a "win-win" situation for public health and environmental protection.

DDT is also used in crop growth, and has been linked to the cause of attention deficit hyperactive disorder (ADHD) and also have an affect on the developing stages for children still in the utero. [verification needed]

Malaria Foundation International[edit | edit source]

The Malaria Foundation International[2] expresses fears of a rush to ban DDT before alternatives are in place, noting that in certain situations (giving the examples of KwaZulu-Natal and Ethiopia) there are few effective or affordable alternatives. Their website states:

  • Malaria and leishmaniasis are diseases that are in resurgence in many parts of the world. Diminished control efforts are, at least in part, responsible for this resurgence (Roberts et al. 1997, Roberts et al. 2000, Baird 2000).
  • The MFI has supported an eventual (not immediate) ban, with the proviso that an effective and affordable replacement is found before DDT is banned.
  • DDT is one tool of many in the malaria control worker's toolbox. The reason that it is being discussed at this site is that, unlike other tools, there is an imminent danger of it being taken away. This puts not just health, but lives, at stake. The MFI wants to see all possible tools for malaria control be readily available, because malaria is a serious, resurgent problem with drug resistance and increasing numbers of illnesses and deaths.[3]

DDT and the POPs Treaty[edit | edit source]

The Stockholm POPs Convention, a treaty to phase out persistent organic pollutants (POPs), including DDT, is currently open for ratification. WWF welcomes this historic agreement which involved provisions for phasing out DDT, while still allowing for its continued limited use for malaria control.

Evidence continues to accumulate about the dangerous health effects associated with DDT. The treaty provisions appropriately balance the need to reduce these hazards while promoting stronger malaria control programs. The accord states that "with the goal of reducing, and ultimately eliminating the use of DDT," individual countries may continue to use the chemical for controlling malaria. However, these countries will also be encouraged to prepare national implementation plans to reduce their reliance on DDT.

Specifically, the national plans would promote methods for reducing illegal uses of DDT, such as agricultural applications. Countries would also identify steps to implement alternative approaches and promote measures that strengthen health care and reduce the incidence of malaria. The parties to the treaty will periodically review the status of alternative approaches to determine whether DDT is still needed or whether it can be eliminated completely.[4]

External links[edit | edit source]

References[edit | edit source]

  1. The Nobel Prize in Physiology of Medicine 1948 Accessed July 26, 2007.
  2. Environmental Health Criteria 9: DDT and its derivatives, World Health Organization, 1979.
  3. Larson, Kim (December 1, 2007). "Bad Blood". On Earth (Winter 2008). Retrieved 2008-06-05.
  4. ""The Bald Eagle - USA's National Emblem"". Retrieved 2009-07-17.
  5. E. Stokstad, "Species conservation. Can the bald eagle still soar after it is delisted?", Science 316, 5832 (2007), p. 1689f. Digital object identifier
  6. "Practical advice should be 'Spray as little as you possibly can' rather than 'Spray to the limit of your capacity'" - quoted at the blog post Rachel Carson: Vindicated!.
  7. Geisz HN, Dickhut RM, Cochran MA, Fraser WR, Ducklow HW (2005). "Melting Glaciers: A Probable Source of DDT to the Antarctic Marine Ecosystem". Environ. Sci. Technol. ASAP: 3958. doi:10.1021/es702919n. Retrieved 2008-05-07.
  8. Toxicological Profile: for DDT, DDE, and DDE. Agency for Toxic Substances and Disease Registry, September 2002.
  9. van den Berg, Henk; Secretariat of the Stockholm Convention (October 23, 2008). "Global status of DDT and its alternatives for use in vector control to prevent disease". Stockholm Convention/United Nations Environment Programme. Retrieved 2008-11-22.

Discussion[View | Edit]

Additional info[edit source]

Category:Mosquito control has some info on DDT.

Also, here's some links from a discussion I had with a friend by email in 2005 - no time to arrange it neatly and put it in the article - perhaps someone else can? One of the most interesting things I learnt was that DDT has not been banned completely, but is used, usually in a limited way, in some countries.

My friend sent this link: Africa needs DDT, not "blah, blah, blah" - Pravda (Yes, the old Soviet propaganda machine!)

My response was: "After reading a couple of things... I think the argument for DDT has been overstated by some people, but it is still useful in certain, very specific applications (e.g. applying to the walls of houses - it lasts for months, and once the mosquitos develop resistance, the newer insecticides remain effective)."

Joe baker vs Donald Johnston[edit source]

A pro-DDT newspaper article was written in 2005 by Joe Baker: Rachel Carson, mass murderer? A rebuttal to was published: "DDT has many drawbacks in trying to stop malaria", by Donald Johnston, The Spectrum, St. George, June 19, 2005 - this is no longer available online, except in the newspaper's archive, behind a paywall. It makes various claims that would be worth checking, so I've summarized them below. Joe Baker's responded with a rebuttal to the rebuttal - this is also available online, so I haven't bothered summarizing: DDT has saved millions of lives.

(Most likely Donald Johnston had a response to that as well, but I haven't gone looking... I think a more profitable next step is to check the facts directly, starting with Wikipedia's entry on DDT and checking the sources.)

Johnston says that:

DDT "is highly toxic to fish and aquatic invertebrates, a teratogen for amphibians, it accumulates to toxic levels in mammals and there is good reason to suspect that it damages the reproductive capacity of birds. In humans, it exerts acute toxic effects. Its metabolites persist in breast milk following cessation of environmental application and there is some evidence it affects mental development in children." (Interestingly, all his evidence for danger to humans is vague, e.g. "some evidence".)
He notes that it is classified as a "probable human carcinogen." (My emphasis.)
"Sri Lanka resumed DDT use following its initial cessation, and then switched to malathion in the early 1970s because DDT failed to stop a malarial epidemic. Why didn't it work? The mosquitoes became resistant."
Some do still use it. "The World Health Organization recommends its use for impoverished countries unable to purchase more expensive alternatives. Therein lies the true attraction. DDT is cheaper, not better,"
He disputes the statistics - "While Mr. Baker incomprehensibly put the incidence of malaria in Sri Lanka at 2.5 million cases annually, the reality is enlightening. The incidence actually peaked over the past quarter-century at 700,000 in 1987, and in 2003,after a 13-year decline, was 10,000with two fatalities nationwide. This success was achieved, absent DDT use, with intelligent public health measures - including insecticide treated bed-nets."

Note on the author: "Donald Johnston holds a PhD in genetics. He developed an interest in malaria while working in the tropics. He lives in Bloomington."

Then there's a blog post with a debate in the comments, including pro-DDT comments by tc: The Great DDT Hoax.

It seems to me that it's more complex than some hardline environmental skeptics will admit (and hardline greenies for that matter, I expect). However, I haven't noticed such unbalanced arguments in my quick look at AAEA's material; they seem to be much more honest, saying that yes, there's a negative impact, but it's small (I don't know if this is true) and it's less significant that the deaths of many people (hard to argue with that).

It should also be noted that there are other ways of reducing the risk of malaria. These should also be used. The GEM method strikes me as particularly clever. But malaria is such a deadly thing it warrants every technique we have, and I think limited use of DDT on indoor walls is probably very helpful, with very little environmental impact.

Another point to watch - one must be careful of stereotyping "greens" as only caring about the environment, and not about people. They do endorse alternatives, but generally do not intend to do so at the cost of a great loss of human life:

Even representatives from the WWF and Greenpeace were quoted in the New York Times on 8 January 2005 as saying that they would accept the use of DDT "if the alternative isn't working as they didn't in South Africa... if there's nothing else, and it's going to save lives, we're in favour of it. Nobody is dogmatic about it. (Pravda article, linked above)

Note also Rachel Carson's comments endorsing limited use of insecticide - noting that limited rather than wasteful use would reduce problems of resistance. Like the economist Adam Smith, she's often portrayed as an ideologue, but appears to have been much more balanced. See this blog post: Rachel Carson: Vindicated!.

Coincidentally I got a very sad SMS two days ago from a good friend, saying that her sister back home in Sumatra had just died of malaria. Life is hard in places like that. --Chriswaterguy · talk 07:41, 28 October 2007 (PDT)

Comment[edit source]

The data I used in my rebuttal to Joe Baker is within data bases and what I considered to be reputable sources online, but also from my memory of the subject when I was interested in it. Its toxicity to aquatic life is not in dispute, and you may look at toxicology sites to assure yourself of that. The general consensus is that some birds, including the peregrin falcon and the bald eagle, were significantly affected by this substance and ecological evidence is consistant with that interpretation: the decline in DDT use preceded a rebound in the population of those birds. The significance of its teratogenecity in humans is unsupported, and its activity in human cancer inconclusive, although it is classed as a probable human carcinogen. DDT does not have to be as horrible as asbestos to be considered a good idea gone bad. DDT had become a paradigm for irresponsibility in my view, since alternatives exist, both in the form of insecticides (pyrethrins) and behavioral modifications. It is used because it is cheap, and therefore reflects a lack of committment to human health, justifying environmental damage because gains in human health, especially infants and children, come with better profit margins and less financial committment to what is essentially an African problem. Offhand, societies that spend trillions on war hardly merit a hearing on why they should save lives with environmental toxins. It is clear they care nothing for life. Until that committment changes, and money flows into the use and development of toxins and strategies for vector eradication that do not threaten the environment, caving in to arguments about the health benefits of DDT use merely displaces the suffering from the jungles and savannahs of central Africa to the killing fields of the middle east. And while the current thought is that limited application of DDT is acceptable, ask yourself why you think that. Who told you that DDT in small quantities is tolerable? These are arguments of ignorance. They may be true, but one already knows that DDT is harmful. Natural selection will act on mosquitoes that need to take a blood meal in order to reproduce, and resistance is predictable wven with limited use. The toxin acts romiscuously on any insect, and so it will continue to enter higher animals that fed on them. The arguments concerning the safety are quantitative ones, not qualitative, and only time will tell if yet another environmental experiment is being run based on the justification of a benefit for human health. If you believe that killing mosquitoes with DDT is a necessary part of anti-malarial strategies, you are accepting second party arguments rather than looking at the primary data. It is not necessary. It is harmful. It becomes useless with the development of resistance in Anopheles. Why would anyone hose down the environment with a useless, toxic chemical? I guess someone can sell it as necessary. If you can buy into war, you can certainly buy into that.

You will also note that Mr. Baker used as a source of authority the American Academy of Physicians and Surgeons. This is a sham medical organization meant to resemble a legitimate scientific society with its own journal, but serves as a pulpit for reactionary polemics, addressing such medically interesting topics as Hillary Clinton, gun rights, thimersol and abortion from predictable positions. Insofar as people are known by the company they keep, Mr. Baker would do well avoid these people. Mr. Baker's rebuttal was indeed met with a response on my part, but it was not published and I no longer have it. He misrepresents claims by a variety of organizations in it likely because his readings on the subject derive from polemics. He, for example, claims that the EPA and the WHO concluded that DDT is not harmful. No, that is incorrect. EPA data and reviews are quite clear on the harmful effects of DDT. [1]. DDT causes cancer in rodent models and is classed as a probable human carcinogen. [2] The WHO considers DDT a carcinogen in animals with other harmful effects. [3]. What the WHO supports is limited indoor spraying in part because the environmental persistence of DDT means it doesn't require as much labor as organophosphates or pyrethrins. [4] . The WHO rejects mechanistic models of human carcinogenicity based on epidemiological data, however any epidemiologist will tell you that epidemiology is not a basis for concluding anything, although it may produce sufficient evidence for resource allocation. In this case the WHO rejects environmental arguments in favor of DDT use. It is understandable, though unfortunate. One might note that the most common hospital admission in the US during the civil war was for malaria, yet there is no malaria in the US now and the US has not used DDT since its ban in the 70's. Eliminating malaria and keeping it out requires committed action across the board of public health, not DDT.

It is an unfortunate principle of the internet that all voices are equal, even those that are fraudulent, and hardly anyone possesses the acumen necessary to identify deceit in advanced technical fields. Our sorry internet democracy is just a way of spreading logical argument disconnected from validity, and so DDT is now a good guy if you need to think so, and the arguments are there spread far and wide thanks to the internet, and with likely millions of fervent believers. Mr. Baker, although I am sure his heart is in the right place, wishing to defend human life, had no justification insinuating that Rachel Carson was a mass murderer. Her work founded the environmental movement and she should not suffer brainless attacks or disgraceful insults so. The understanding her work engendered actually defends human life far better than any toxic chemical because it defends all life against human arrogance.

—The preceding unsigned comment was added by Prospero, 29 March 2009

DDT is a very emotional issue, and I'm sure most visitors to this site would consider it as something to be avoided. Regardless, it's an appropriate subject for discussion and analysis. The key pieces of analysis are:
  • A cost-benefit analysis for the specific use case proposed. (Very different if we're looking at limited application to walls, as opposed to the carefree spraying of the 1950s)
  • Environmental impact assessments - really a more formal cost-benefit analysis, I think.
  • Detailed comparison with alternatives, considering real-world use. E.g. bednets, whether people use them, and noting that they protect against malaria but not dengue
Remember that "the poison is the dose" and if it turns out that a tiny amount of DDT applied to walls saves lives, with minimal leaching into the ecosystem, then it's appropriate to describe that here.
If it turns out that it's not worth the environmental cost and/or there are always better alternatives, then this page should explain why that is so. For this reason I'm removing the delete tag placed by an anon editor ({{delete|Completely at odds with the AT-phylosophy; at the very least the insecticide needs to be organic/biodegradable; DDT stacks up in each animal of the food chain instead}}) --Chriswaterguy 03:41, 8 January 2011 (PST)

Impact of cutting back DDT use?[edit source]

Science writer Fred Pearce made the (vague and unsupported) statement here that:

"When Rachel Carson’s sound case against the mass application of DDT as an agricultural pesticide morphed into blanket opposition to much smaller indoor applications to fight malaria, it arguably resulted in millions of deaths as the diseases resurged."

Tim Lambert often vocal on this issue) responded by plotting a spike in DDT use in India during a malaria resurgence in the 1970s. He states:

"It is arguable whether the increased use of DDT caused a resurgence in malaria (by promoting DDT resistance in mosquitoes) or alternatively the resurgence caused an increase in DDT use in an attempt to get it under control, but it cannot be honestly argued that a blanket ban on DDT caused the resurgence."

More responses to Pearce are found below the original article, in the comments. Commenter Joshua writes:

"...please point to one study that makes a serious attempt at controlling for the effects of continued widespread agricultural usage of DDT. In order to refer to a counterfactual (in the sense of speculation about what might have happened) quantity of deaths absent the opposition - you need to deal seriously with what would have happened, er, absent the opposition - in other words more widespread resistance. Please also note that proper usage of DDT requires well-funded and organized governmental infrastructure - features that were absent due to the same lack of funding that prevented other effective means for controlling malaria (draining swamps, building good housing, nets, etc.) from being maximally implemented.
"Please also note that DDT was not banned (or even the subject of treaties as opposed to to false claims of "bans") for vector control (although the opposition to indiscriminate agricultural usage did lead to less usage for vector control).
"Please note that in some areas usage of DDT for agricultural purposes continued with a negative impact on rates of malaria.
"DDT is not a magic bullet that would have saved millions of lives. It certainly could have been used more effectively than it has been used, but your reference here was sloppy."

Commenter thingsbreak refers to a metaanalysis of the causes of a malaria resurgence, and states:

"The drop off in DDT use in fighting malaria was not due to some sort of environmentalist groundswell. Programs with a deliberate time limit, complacency with results, budget shortfalls, political mismanagement and instability, and resistance were all contributing factors. "Greens" were not. Of the handful (9 percent) of cases of decline in community acceptance, the cited causes were resistance and perceptions that the programs were just not working, not fears about DDT safety."

Commenter Ed Darrell states "Even under the 2001 Persistent Organic Pollutants Treaty (POPs), any nation may use DDT, simply by sending a letter to WHO saying it intends to use it." and "indoor residual spraying (IRS) has never gone out of style. Not sure who is claiming environmentalists opposed it, but that's not accurate. In fact, EDF, the group that first sued to stop DDT applications anywhere, has long endorsed use of DDT in Africa and Asia for IRS. " - among other interesting points.

--Chriswaterguy 05:37, 23 February 2013 (PST)

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