forum discussion #4

DDT vs. Malaria: The Lesser of Two Evils?

May Berenbaum

May Berenbaum

Malaria is one of the world’s deadliest diseases. The mosquito-borne illness kills about a million people every year, mostly children in the developing world.

DDT is one of the world’s most vilified chemicals. The insecticide caused widespread environmental harm when massive amounts were sprayed on crops a half century ago.

Some African governments (with support from the United States) are now fighting malaria with DDT, but some Africans fear the prevention efforts are worse than the illness. Listen to our recent story from Uganda.

In this World Science Forum, we talk to May Berenbaum. She’s an entomologist — an insect expert — at the University of Illinois at Urbana-Champaign.
Continue Reading ...

Read her essay about DDT and malaria in the Washington Post.

And check out her new book, The Earwig’s Tail: A Modern Bestiary of Multi-legged Legends.

We spoke to Berenbaum.  Download the interview, or listen here:

Audio clip: Adobe Flash Player (version 9 or above) is required to play this audio clip. Download the latest version here. You also need to have JavaScript enabled in your browser.

Now it’s your chance to ask the questions. Join our conversation with May Berenbaum.

Malaria mosquito, MARTIN DOHRN/SCIENCE PHOTO LIBRARY

Malaria mosquito, MARTIN DOHRN/SCIENCE PHOTO LIBRARY

Would you allow the government to spray DDT in your home?

Is it hypocritical for the U.S. to ban DDT at home yet promote its use abroad?

In parts of the world dealing with a health emergency like malaria, is worrying about DDT’s potentially harmful effects a luxury they can’t afford?



Hide

The guest has left this discussion, but feel free to leave your thoughts.
 

Your Comments

  1. Barmak Kusha

    DDT is 1 of several arrows (including pyrethroids, carbamates, etc.) in our quiver on the indoor residual spraying (IRS) aspect of the US President’s Malaria Initiative (PMI), a contract held by RTI, International. it is cost-effective, used with the highest safety standards.

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? David Baron

      Thanks, Barmak. I’m The World’s health and science editor. I’m curious about your experiences working in Africa. Does DDT generate more controversy than those other arrows in your quiver — the pyrethroids, etc.?

  2. Barmak Kusha

    Hi David, nice to meet you virtually and thank you for your question. The answer is in some countries, yes it does. You can just do a news search for “IRS AND spraying” or “malaria AND spraying” and you’ll see several controversy-related articles come up, for Uganda, for example, or Ghana. Other countries, some right next door, not at all.

  3. Donn Dimichele

    I worked in a DDT manufacturing plant for four summers while going to school. We worked in close contact with it constantly, with no protective gear beyond hard hats and safety glasses. I ingested large amounts of DDT in solid and aerosol form and my skin and clothes were covered with it following every shift. I suffered no known ill effects — it’s now 36 years later — nor did any of my coworkers, even those who spent 20+ years at the plant. In fact, the incidence of cancer among the workers was slightly less than that of the overall population. In view of my experience, I’m not at all concerned that using DDT against anopheles mosquitoes will endanger humans. The possible effects on wildlife — one reason DDT is effective is because it stays in the environment for a long time without degrading, and can become concentrated in animal tissue — are less certain, and use of the chemical should be scrutinized for that reason. Given the magnitude of the malaria problem, though, I hope that misconceptions about DDT will not prevent its use where it can make a valuable contribution without unacceptable environmental costs.

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      It’s true that DDT has a better safety record than a lot of other synthetic organic insecticides (particularly the organophosphates, which can be acutely toxic to humans). There are some studies that suggest there are neuroendocrine impacts if exposures occur early in development but evidence for carcinogenicity is equivocal. An increasing concern about the use of DDT in Uganda, though, is coming from growers of organic crops (particularly cotton), which bring in greater profits; exposure to crops to DDT during storage may cause buyers to reject them as organic. Thus, there’s a new economic angle to consider in discussions of DDT–demonstrating that the story is continuing evolving…

    • Jerry Giambeluca

      I also worked in a DDT manufacturing plant in California called Montrose Chemical Co many years ago. At the time I worked there we were told there was a government study going on at the plant to see if DDT was preventing cancer.
      In later years, I read all the stories in the news that DDT was a cause of cancer, how it hurt birds and fish, etc. I assumed that the study the company originally told us was a cover story, to protect themselves and confuse the workers.
      For many years I worried that I would surely come down with cancer, or some giant goiter, or some other gruesome defect.
      Well, I’m now 70 years old, have no bad effects, and I’ve found out the original study the company told us about was actually done by the government and the study found that no-one who worked there had gotten cancer in at least 20 years. That’s quite an amazing result for a known carcinogen.

  4. Julius Kerr

    Back in the 1960′s we remember big trucks driving through the neighborhood spraying chemicals to kill mosquitos. We were told to stay in our houses while they were spraying. As children, we did not always stay inside. Now at the age of 60, I have a neurological condition that no one is able to diagnose or cure. Wondering if there is any connection between my mystery neurological condition and the spraying of those chemicals? Should we attempt to find out what chemicals were used?

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      i’m a baby boomer myself and vividly remember the trucks from growing up in Levittown, PA; in fact, there’s a Facebook group “Levittown PA through the eyes of the baby boomers” with an entire page devoted to people’s memories of the spray trucks. With 20-20 hindsight as an entomologist, I can’t help wondering who at the time thought that was a good idea and whether there have been long-term consequences.
      I’m not sure, though, that there’s any effective way of finding out what was being sprayed in particular neighborhoods (I suppose one could pore through newspaper archives from the time but my guess is that newspaper accounts wouldn’t name the chemical–no one was especially concerned). As for linking exposures through childhood to a current condition, sad to say, human lives are so complicated that establishing a definitive link would require a controlled massive retrospective epidemiological study and considerably more knowledge of the etiology of disease (and the contributions of individual genotype) than currently exists.

  5. Being a birder and an enthusiastic lover of nature, I was a bit disturbed to hear your comments about DDT without mention of the long lasting environmental effects of this chemical, except when the interviewer mentioned Rachael Carson. I hear what you are saying about using this chemical intelligently and only when effective, but I worry that with so much that is cheap and abundant, it will used indiscriminately, especially in the emerging world where malaria is so prevalent. I would hope we could expand the horizon for effective anti mosquito treatments that are less hazardous to the reproduction of birds specifically and the environment in general.

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      You’re absolutely correct that DDT has demonstrable adverse nontarget effects on birds, particularly raptors and other predators (not to mention its nontarget effects on a wide range of other creatures, including beneficial invertebrates). One of the arguments for indoor residual spraying for malaria in Africa (and one reason I didn’t dwell on impacts on birds) is that, in theory, keeping the pesticide indoors is designed to minimize nontarget exposures in the environment. That said, however, there’s a legitimate concern that, once a cheap and extremely effective insecticide can be easily obtained, it can also be abused– that DDT will be diverted for illegal agricultural use, and environmental exposures will be inevitable. Off-label use of pesticides is a problem everywhere, not just in Africa, and is difficult to detect and prevent.

    • Paul Saoke

      Dear May,
      The practical experience with DDTspraying in Africs is that the chemical is widely abused in countries like Ethiopia where farmers use it in Agriculture. We have also seen the buse in Uganda where spray teams dump remains of DDT in ant hills.

  6. Dear Ms. Berenbaum:

    DDT has been shown to be effective against even DDT-resistant mosquitoes, because it acts as a repellent. Most mosquitoes, resistant or not, will not enter a house whose inside walls have been sprayed.

    See this interview with entomologist Donald
    Roberts for documentation:
    http://www.21stcenturysciencetech.com/
    2006_articles/Donald_Roberts.pdf

    Sincerely,
    Marje Hecht

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      That’s true but only to an extent–it’s very difficult to generalize about the behavior of DDT-resistant mosquitoes because resistance can arise in so many different ways. Physiologically resistant mosquitoes can, with sufficient selection pressure, evolve resistance to the repellent effects. There’s a long history of the evolution of behavioral resistance in mosquitoes, even in Africa–in the 1950s, indoor spraying selected for populations of mosquitoes that avoided indoor walls entirely and rested on exterior walls.
      Donald Roberts has worked extensively on the behavioral responses of mosquitoes, including resistant mosquitoes, but some of the most thorough field studies (e.g., Grieco et al. 2007 PLoS One
      http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0000716
      have been on Aedes aegypti, the yellow fever mosquito, which is not a vector of malaria. It’s difficult to predict a priori which physiologically resistant A. gambiae populations will be repelled by DDT. Unfortunately, malaria in Africa is staggeringly complicated.

  7. Dear Ms. Berenbaum:

    I think you are dancing around the main point here.

    One child dies every 30 seconds from malaria in Africa. The WHO in 2006 reversed its earlier decision and allowed the use of DDT for Indoor Residual Spraying because it was most effective for this use.

    South Africa, which stopped DDT, saw a rapid growth of malaria, and then returned to DDT use to dramatically stop the incidence and spread of malaria. Other African countries, where malaria is one of the top killers, would like to use DDT for IRS, but they are stopped by the green lobby and misinformation.

    Yes, malaria may be a “staggeringly complicated” problem. But the solution isn’t so complicated unless one makes it so, as the population control lobby has intentionally done, because they see malaria as helpful.

    Sincerely,

    Marje Hecht

    P.S. Entomologist Don Roberts spent 40 years, much of it in the field, studying malaria and DDT. I think he knows what he’s talking about.

  8. Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

    ?? I wasn’t trying to dance…I’m fully aware of the enormous human toll of malaria–you’d be hard-pressed to find an entomologist who isn’t– but I’m not certain why you’re invoking the “green lobby” in the case of Uganda. DDT was used by Uganda’s government, with the encouragement (and financial support) of the United States, in Apac and Oyam. Problems arose due to local objections, not due to external forces. Although some of the objections arose from profoundly misplaced concerns about human health impacts, at least in part there were concerns about the impact of IRS on the commercial viability of organic cotton grown in the region; DDT residues may exclude the cotton from the organic market,which pays a valuable premium that would be economically damaging to lose. This is a new wrinkle in the discussion of IRS, which is why I said the issue is complicated.
    For the record, I have no problem with IRS using DDT in Africa, but I think resistance monitoring should be a part of any pesticide-intensive program, in Africa and elsewhere. As you point out, Don Roberts has spent many years working on malaria, as have many others, including Maureen Coetzee and Janet Hemingway, both of whom have documented resistance to DDT and other pesticides throughout Africa.

    • none of those mentioned is an african. listen research by Kenyan doctors who are Africans and speak for Africans. DDT has no effects on human and should be allowed to be used! period! You cannot tell me birds are important than humans.Stop western government from playing fiddle with policies. United States allow Africa to use DDT to some extent and then collude with EU to ban exports from countries that are using it.
      The ‘poor’ African nation has no other means than to stop using DDT so it products will be accepted on EU or US market. If not, then their economy will collapse and the evil effects of poverty spread through out their region.

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      I believe that Maureen Coetzee is South African;; she has been working in South Africa since 1969 and she earned her master’s and PhD degree from University of the Witwatersrand. She currently holds the National Research Foundation Chair in Medical Entomology and Vector Control, Division of Virology and Communicable Disease Surveillance, University of the Witwatersrand is also affiliated with the National Institute for Communicable Diseases (NICD), Johannesburg, Private Bag X4, Sandringham 2131, South Africa
      http://web.wits.ac.za/NewsRoom/NewsItems/COETZEEINUAGURALLECTURE.htm

    • Paul Saoke

      Kwabena is not knowlegeable on the matter and talks about kenyan doctors who have done research on the matter. I am a Kenya and have stayed with the issue since 1998 and have never seen any publication by a Kenyan that he could be referring to. There are studies which only documented the DDT chemical body burdens (For example Kahunyo et al. in the East African medical Journal studied organo-chlorine pesticieds in chicken eggs, Leiticia Kanja – another Kenyan studied the dDT concentration in human breast milk in Kenya way down in 1986. I do not think that it is fair to evoke emotions of Africans versus the rest of the world. What i know is that Americans are at the fore front of championing DDT use in Africa and that fit within the neo-conservtive ideology which has changed now even though there are still hangovers. I see elsewhere people quoteing concocted statistics about African children dying every second – basically hperbolic statements that do not have scientific basis. People sjould realize that the people who coined these statements were funded by corporations and we have evidence to that extent. Malaria in Africa is over estimated and misdiagnosed. A recent journal article of research conducted in Kampala uganda indicates that anybiody who presents with fever is treated for malaria – presumptive treatment which in itself poses serious problems. I know many South African scientists who have published on the health effects of DDT. Prof Christian De, Jager and Prof Rianna Bornman have published extensively in peer reviewed journals yet their works are not highlighted since they do not take any political angles. Kwabena do you listen to only Africans or humanity is the same regardles of colour?

  9. Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? Elsa Youngsteadt

    Several podcasts ago, we talked about a paper in the journal PLoS Biology which argued in favor of “evolution proof insecticides” that kill only old mosquitoes.

    Since older mosquitoes are the ones transmitting malaria, this approach would still help control the disease. But since the mosquitoes would have already reproduced before dying, there would be no advantage to being insecticide-resistant– hence “evolution proof.” The paper is here http://tinyurl.com/lwpzja

    It seems like a beautiful solution… but is it plausible? How does the idea fit into the DDT-Malaria discussion?

    Thanks!

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      The article in PLoS Biology is a terrific example of applying evolutionary theory to practical problems and the approach of late life-acting insecticides holds great promise. I’m not sure, though, that I would ever have the confidence to predict that these insecticides will be “evolution-proof;” random mutation and sufficient selection have a way of breaking down seemingly insurmountable barriers (e.g., crop rotation-resistant rootworms here in the Midwest). At the moment, the approach is theoretical and the authors themselves point out assumptions that must be met in order for insecticide longevity to result. Among these–that resistance exerts a cost (not always easy to document), and that the Plasmodium parasite won’t be capable of evolving a shorter lifespan (which remains speculative).
      I would like to point out, too, that these authors recognize the value of monitoring levels of resistance in management programs (e.g., p. 5)

  10. The Roberts paper on DDT as a repellent is actually not that ground-breaking. Here is a review:
    http://membracid.wordpress.com/2007/08/09/an-odd-email-campaign-by-africa-fighting-malaria/

    Roberts is an entomologist–and he also is closely tied to Larouche’s organization, as are you Marje.

    The issue of resistance is a very complex one biologically–multiple vectors, disease strains and resistance mechanisms. There is not a one-size-fits-all solution, DDT or otherwise.

    Please answer this question Marje:
    Why, if insects are *already* resistant to DDT, and we have other compounds that perform as well or better with less risk of resistance and toxic effects for both people and environment, is your organization so determined to promote using DDT?

    • Paul Saoke

      Karl,
      It is important to note that the WHO’s international Program on Chemical safely (IPCS) has been reviewing new evidence of DDT toxicity but has kept its release postponed since 2006 to date. Weare not even sure that it will see the light of day. Secondly the landmark Pine river statement should be a popinter of what to expect from the IPCS review. You are right karl that the issue is not DDT versus malaria. People die from malaria because they do not get treated from it.

  11. Thanks for bringing attention to this important issue. There are two points which I’d like to make, and I’m curious to hear what Prof. Berenbaum thinks.

    1. The commenter above is in incorrect–as is much of the media–in stating that the WHO reversed it’s position on DDT in 2006. The fact is that WHO has always recommended DDT as one of 12 insecticides for use in IRS campaigns targeting malaria. It’s recommended dosage, 2 g/m2, hasn’t changed in years, either. The only thing that changed in 2006 was that in addition to recommending IRS (with DDT or with any 11 other insecticides) in areas of episodic transmission, the WHO now also recommends IRS in areas of constant, endemic transmission. Despite the strongly worded press release by Arata Kochi, there was no “new” assessment of DDT’s health effects, and the policy change related to IRS in general, not DDT specifically. It’s interesting to note that in 2009 the WHO announced it’s intention of a ” total phase-out [of DDT in IRS] by the early 2020s if not sooner.”

    2. What often gets lost in the discussion of DDT is the fact that there are a plethora of alternatives to DDT. Despite the title of this very page, it’s not a question of spraying DDT or letting malaria ravage the tropics. DDT is one 12 insecticides recommended and approved by the WHO for IRS; IRS is just one of several strategies for vector control (others including nets, larvacides, and a variety of environmental management strategies); and vector control is just one pillar of a malaria control strategy which ideally should also involve prompt diagnosis and treatment of malaria cases with appropriate drugs. DDT may have been the state of the art in malaria control in the 1950s, but its 60 years later now, and we have new drugs, new pesticides (which aren’t persistent organic pollutants, but which have their own toxicity issues), and a new understanding of how environmental management can exacerbate or eliminate mosquito breeding. And resistance issues have greatly reduced the efficacy of DDT, and it’s use was never efficient in areas where vectors are active during the day or don’t rest on interior wall.

    DDT Is not a magic bullet, it won’t work by itself, and it shouldn’t be the first line of defense. To me, the questions we should be asking are how much of a role should DDT play in a diverse mix of strategies. Why did the Ugandan government decide to use DDT and not a different pesticide, or a mix of pesticides. Why not distribute (more) bednets? Why not beef up the public health infrastructure, which unlikely IRS would have collateral benefits rather than causing collateral damage to health, the environment, and the economy. Why not do all of these things? And why aren’t we asking these questions rather than focusing on the IHMO misdirected question of DDT vs malaria?

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      Thank you for your balanced and insightful analysis! DDT is a curious anomaly in the armamentarium of pest management; I think, because it was the first successful (and dirt-cheap) chlorinated hydrocarbon to be used and the first (extraordinarily environmentally persistent) to be banned, it has acquired iconic status on both ends of the continuum. You’re absolutely right that there are many other tools that are already available and if the past forty years have taught us anything it’s that there is tremendous value (economic, evolutionary, and even political value) in diversifying the toolbox. That was the main conclusion of the 2000 National Research Council report on the future of pesticides in U.S. agriculture and it’s no less apt in discussions of malaria (or any other insect-borne disease) management.

  12. Ferdinand Engelbeen

    Dear May,

    Several questions:

    - If DDT is mainly used as repellent by inside spraying, how can that increase the resistance of mosquito’s against DDT?
    - If the repellent function of DDT gives a shift towards other mosquito species which work outdoors during the day, doesn’t that apply as good for other indoor uses like pyrethrins?
    - The cost effectiveness: Many African countries lack money and health care infrastructure. DDT need to be sprayed inside houses only a few times per year, pyrethrins many times. Besides the price of the alternatives, is the lack of infrastructure not one of the best reasons to use the most cost effective control?

    I don’t think that DDT is THE solution, neither are the alternatives. And indeed a mix of possible controls is the best way. But in a lot of African countries, the cost is the most important factor…

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      Insecticides don’t need to kill insects to select for resistance–all they have to do is reduce the ability of an insect to survive and reproduce. It’s important to remember that there are many different kinds of resistance–”resistance” doesn’t just equate with the ability to metabolize a pesticide to render it harmless. Behavioral resistance to repellency can evolve in any of a number of ways. Such evolution is less likely to occur in species that feed on a broad range of hosts–once repelled, such a species can go off and feed on an alternate host–but Anopheles gambiae, the principal malaria vector in many parts of Africa, feeds only on humans so any genetic change that increases the likelihood of encountering a host and obtaining a blood meal would likely be selected for. There is evidence of genetically based variation in sensitivity to DEET, the repellent used most widely against mosquitoes, at least in the laboratory–e.g., Klun et al. 2004, Comparative Resistance of Anopheles albimanus and Aedes aegypti to N,N-Diethyl-3-methylbenzamide (Deet) and 2-Methylpiperidinyl-3-cyclohexen-1-carboxamide (AI3-37220) in Laboratory Human-Volunteer Repellent Assays
      http://www.bioone.org/doi/abs/10.1603/0022-2585(2004)041%5B0418%3ACROAAA%5D2.0.CO%3B2
      And cost-effectiveness is absolutely a factor in malaria management in Africa and I believe it’s one of the principal arguments for using DDT. But the case in Uganda appears to be unique in that at least one segment of the local population is unhappy with the prospect of losing the premium associated with the sale of organic cotton as a result of pesticide contamination (which is, at base, an economic consideration).

  13. I’ve been following this issue for years, but especially since Rachel Carson’s 100th anniversary year and the kerfuffle in Congress over naming her town’s post office for her.

    I have bunches of questions – here are a few.

    First, what would be the ideal way for Americans to contribute to beating malaria in Africa and Asia?

    Second, there are claims that birds, especially eagles, did well with DDT. I can’t find any science papers to back these claims, but maybe you know of some?

    Third, is DDT the insecticide of choice to beat West Nile? A lot of people claim it should be. If not DDT, what?

    Fourth, what would be the insecticide of choice to beat back bed bugs? It’s popular now to claim that bed bugs are back only because DDT use has been stopped.

    Thank you and PRI for this forum. Best and highest use of radio waves and internet band width, all in one.

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

      In response to the question as to how Americans can contribute to managing malaria, certainly supporting ongoing efforts on the ground in Africa (there are several nongovernmental organizations dedicated to obtaining, securing and maintaining insecticide-treated bednets, for example) but supporting research that can lead to novel environmentally sustainable approaches is also important (the Gates Foundation has been instrumental in this regard). Raising awareness is critical, too–because malaria isn’t an American problem, many people are completely unaware of its global impacts.

      As for the claims that “birds, especially eagles, did well with DDT, ” I have to admit that’s news to me. There’s an extensive literature documenting declines of birds of prey that correlate with DDT use as well as laboratory studies that demonstrate adverse impacts of DDT on calcium metabolism in birds that contribute to eggshell thinning. I don’t know of any study showing that DDT is good for eagles..
      .
      In terms of West Nile, there’s no need here in the U.S. for DDT–as a wealthy nation we can afford to use equally effective insecticides that lack the nontarget adverse impacts of the chlorinated hydrocarbons. Moreover, the CDC advocates awareness and prevention–reducing the likelihood of getting bitten by mosquitoes with the use of repellents, timing of outdoor activity, and sourc reduction by eliminating breeding places also reduces the likelihood of infection.

      Finally, bed bugs are back not because DDT use declined but rather because global trade increased, second-hand markets have expanded, bait-based cockroach control has become more popular, and possibly even because attributes of the biology of the bed bug may have changed that have led to an increase in abundance.
      If anything, DDT is likely to be less effective against bed bugs than it was 60 years ago because of resistance problems (e.g., Karunaratn et al. 2007, Insecticide resistance in the tropical bedbug Cimex hemipterus Pesticide Biochemistry and Physiology 88, 102-107; AGEM, Ronaldo L. and WILLIAMS, Paul. Susceptibility tests of the bed-bug Cimex lectularius L. (Hemiptera, Cimicidae) to DDT in Belo Horizonte, MG (Brazil). Rev. Saúde Pública [online]. 1992, vol.26, n.2 [cited 2009-05-07], pp. 125-128. ISSN 0034-8910. doi: 10.1590/S0034-89101992000200009). In the U.S., pyrethroid resistance is widespread (Romero et al. 2007, ournal of Medical Entomology 44(2):175-178. 2007
      doi: 10.1603/0022-2585(2007)44[175:IRITBB]2.0.CO;2
      nsecticide Resistance in the Bed Bug: A Factor in the Pest’s Sudden Resurgence?)

      And, finally, thanks for your interest in this important issue!

  14. Ellady Muyambi (Uganda)

    Dear May,
    Thank you for your love for DDT and your endeavours to control and get rid of malaria. Below are my brief points for your consideration in your endeavours to promote the use of DDT indoor residual spraying (IRS) for malaria control especially in Uganda’-
    1. Uganda has the third highest burden of malaria disease in Africa (Malaria report, 2008) but that does not guarantee that Ugandans are desperately in need of DDT;
    2. Malaria is a problem in Uganda not due to lack of DDT. The problem of malaria in Uganda is exaggerated by reduced funding for malaria control programs in the last years, the resistance of mosquito vectors to insecticides and to drugs, limited research on new malaria drugs for over the last 20 years, human population growth and movement, land-use change, and deteriorating public health infrastructure, changes in temperature, rainfall, and humidity as well as the level of immunity;
    3. Most of the people in Uganda who want us to use this scorched earth weapon (DDT) may probably not even be aware of the reprotoxicity of synthetic chemicals because they were not taught that in their schools and they have heard no access at all to journals where these are published. They may not even be aware of the links between synthetic chemicals like DDT (xeno-estrogen) and endocrine disruption;
    4. Uganda acceded to the Stockholm Convention on Persistent Organic Pollutants (POPs) on 20th July 2004 and this binds it to its full implementation of the convention and this includes its commitment to eliminate DDT;
    5. Indoor residual application of DDT may have little impact especially where the Malaria vector tends to rest and bite outdoors and does not enter houses;
    6. The effectiveness of indoor residual spraying of DDT may be undermined if it is poorly accepted by the targeted populations and this has already happened in Uganda;
    7. Whereas it is assumed that DDT IRS is cheap compared to other alternatives, it is well known that the operational costs for DDT IRS application in a widely dispersed and isolated population such as the one of Uganda makes it more expensive than any option. This cost is further exaggerated by the need to have trained technicians, legal and institutional framework as well as specialized equipments for transportation, storage and disposal;
    8. The use of DDT IRS will not only negatively affect the health of Ugandans and the environment but it will also negatively affect Uganda’s economy. Uganda is an agricultural country and therefore using DDT will destroy her agricultural export market potential;
    9. The recent information by the National Environment Management Authority (NEMA) inventory report on POPs, indicate that Uganda has no capacity to use DDT IRS to the standards required by World Heath Organization (WHO). Malaria is not like HIV/AIDS, Ebola or SARS which do not have known cures. Malaria is transmitted from humans to humans, and appropriate control measures should be anchored in eliminating the parasite from the human host while promoting personal hygiene and better sanitation practices;

    Note: Whether you are advocating for DDT IRS or not, our conclusion and determination as Ugandans is that Uganda will not use DDT. We have researched about this old fashioned chemical, seen how it was used in a fire brigade approach in Oyam and Apac districts and came to a conclusion to oppose it by whatever means. A new court case is awaiting and the Ministry of Health can not use DDT now before the court verdict. We are sorry for interfering with your cake. Try to support it in other countries but not Uganda.

    • Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? David Baron

      Thank you for your extensive comments. Our readers might be interested to know, as you indicated in a separate e-mail to me, that you are with the organization Uganda Network on Toxic Free Malaria Control.

  15. Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

    ?! Well, this is the first time I’ve ever been accused of being a DDT-lover! One reason that I was a little reluctant at first to participate in this program is that I’m actually NOT involved in malaria management–my only experience in Africa to date was attending the International Congress of Entomology in Durban last summer. So I’m not a malaria expert and I have tremendous respect for the entomologists who are tackling this incredibly daunting problem.
    As for my endeavoring to “promote the use of DDT indoor residual spraying (IRS) for malaria control especially in Uganda,” well, that statement is simply baffling. I agreed to become involved in this discussion because the opposition to DDT for IRS in Uganda clearly came from Ugandans for economic reasons (organic cotton), and not from developed-world environmentalists, a novel development in the history of DDT. I’m on record, actually, in a Washington Post editorial, stating that DDT use in Africa was not a particularly desirable option and in many circumstances shouldn’t even BE an option (e.g., where resistance has arisen or persisted). So not only do I not love DDT, I don’t even like it very much…
    So, it’s not surprising that I agree with all of the points you’ve made. A high rate of malaria does not immediately translate into a need for DDT; lack of infrastructure and lack of funding for malaria control programs are crippling problems (infrastructure is in issue not just in Africa–when West Nile struck New York City, the city had all but abandoned its mosquito surveillance program, to its lasting detriment). Many of the voices calling (vociferously) for reflexive use of DDT absolutely do not spend a lot of time and effort documenting adverse impacts; I’ve written extensively about selection for behavioral resistance (e.g., exophily), which would render IRS far less effective (here in this forum, actually!). And no spray program, IRS, broadcast, any type, will work unless the human population is supportive of the program (witness the petitions filed in California to protest spraying of pheromones to control light brown apple moth).
    In summary, then, I’m not at all certain how you got the idea that I’m advocating for DDT IRS; most actual DDT advocates consider me a pointy-headed treehugger. I have no cake at all in this discussion and I urge you to go back and read the posts here…

  16. Ellady Muyambi (Uganda)

    Dear David and May,
    As indicated in my separate e-mail to David, I work for the Uganda Network on Toxic Free Malaria Control (UNETMAC) as the Secretary General. UNETMAC is a registered non- for profit, non- governmental organization and an umbrella organization which co-ordinates, supports and builds capacity for its partner organizations to engage in malaria control initiatives without using dangerous toxic substances. As regards to previous comment to May Berenbaum, it’s unfortunate if I mistook her for supposedly supporting DDT IRS in Malaria control programmes. I have read some of her publications and am now clear of her position. I just wanted to clear the glitch that DDT in Uganda is opposed due to economic gains. There is a compendium of issues why we are opposed to DDT. For instance, while DDT IRS was used in the formerly Kigezi district during the 1959-1963 in the area of Rwangaminyeto (Kihihi in the presently Kanungu district), it is vital to acknowledge the fact that the metabolites of DDT then used are still present in the bodies of the residents and other environmental specimens in the said areas and even in areas such as Nyarusiza in Kisoro district where DDT was not used and that these residents are suffering from the negative health effects from DDT exposure. This is well indicated in unpublished study done in 2006 by G. S. Bimenya et al, the head of Pathology Dept. Faculty of Medicine, Makerere University, P. O. Box 7072 Kampala.

  17. Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? May Berenbaum

    Thanks to all who commented on this complex and challenging issue. It’s amazing that, on the 70th anniversary of the discovery of its insecticidal properties in a laboratory in Switzerland, DDT continues to make headlines and create controversy. In closing, I’d just like to make the plea that parties on all sides of this issue remember to take advantage of seven decades of acquired knowledge about DDT’s strengths and weaknesses and make decisions based on data–not only with respect to DDT use in Africa for malaria but for pest management problems around the world.

  18. Thank you for your sensible critique. Me and my neighbor were just preparing to complete some analysis about this. We acquired a seize a e-book from our local library but I think I discovered much more from this post. I’m really glad to determine these kinds of wonderful facts getting shared freely available.

  19. Hey there, I find your internet site to be particularly valuable.

Add your comments

 characters available