Clueless pro-DDT article in the Washington Post

"Nowhere is mentioned the main reason why anti-malaria programs have shifted away from DDT—the widespread development of resistance to DDT by mosquitoes."

This is false. The link is giving examples from only one small country, and ignores some of the other variables involved in said country.

"Other insecticides and drugs against malaria are ignored"

This is true.

"South Africa did reintroduce DDT for spraying traditional houses, but they also used deltamethrin on western-style houses and switched to a more effective anti-malaria drug"

This is irrelevant. Do the various 'cocktails' for HIV/AIDS treatment prevent infections?

"Nowhere does it mention that the ban on agricultural use of DDT that Silent Spring saved lives by slowing the development of resistance against DDT"

This could be true but is too simple an argument. It could also be wrong.

This is getting a bit old. So the answer to Mallaby's question about who is ignoring science now (in this case) is: Tim Lambert

cs says:

>Do the various 'cocktails' for HIV/AIDS treatment prevent infections?

They would if they eliminated the virus from the body. Do you understand how malaria is transmitted? If drug treatment reduces the number of people with the parasite, then fewer mosquitoes will be infected and fewer people will be as well.

And there is this on the agricultural use of DDT causing more malaria:

>"Correlating the use of DDT in El Salvador with renewed malaria transmission, it can be estimated that at current rates each kilo of insecticide added to the environment will generate 105 new cases of malaria." (Agricultural production and malaria resurgence in Central America and India, Chapin, Georgeanne & Robert Wasserstrom, Nature, Vol. 293, 1981, page 183).

Tim Lambert wrote,

If drug treatment reduces the number of people with the parasite, then fewer mosquitoes will be infected and fewer people will be as well.

So I take it malaria lives only in mosquitos and humans?

2: "They would if they eliminated the virus from the body. Do you understand how malaria is transmitted?"

Yes, do you understand how HIV is transmitted?
They don't eliminate the virus but reduce it greatly, quite similar to the antimalarials and the plasmodium species.

"If drug treatment reduces the number of people with the parasite, then fewer mosquitoes will be infected and fewer people will be as well"

Will you advocate for the drug "cocktails" to be used to prevent HIV infections too, or will you see what I meant when I said *irrelevant*?

3: "And there is this on the agricultural use of DDT causing more malaria:" This simple correlation looks to be published in 1981, well before the mechanisms of DDT resistance were well understood. The current locations with large level endemicity wrt malaria are in SSA.
DDT is banned for agricultural use but pyrethrum and synthetic pyrethroids are used abundantly. (coming mostly from Kenya I believe) The pyrethrum targets some of the same voltage gated sodium channels as DDT. The widespread agricultural use of pythrethroids in the region causes vector resistance to both pyrethroids and DDT. A double-knockout. The argument that an agricultural ban on DDT saves lives by slowing resistance to DDT is simple and would only be likely to be true if pyrethroids were banned from agricultural use as well.

I've brought this up previously on this blog, which is why my first comment in this thread was a bit 'snappy'.

liberal: "So I take it malaria lives only in mosquitos and humans?"

Nah, humans and other primates, rodents, canines, birds, reptiles, you name it...

liberal: "So I take it malaria lives only in mosquitos and humans?"

Nah, humans and other primates, rodents, canines, birds, reptiles, you name it

Misleading. Plasmodium falciparum is a human parasite; other species have their own malarial parasites, but they aren't zoonoses, as far as I know. So as far as we're concerned, yes, malaria only occurs in humans and mosquitoes. Am not sure about the other species of Plasmodium that affect humans, but as I recall, they're human-specific as well.

I would stay away from claiming DDT causes cancer. If so, it is an extremely weak carcinogen, and much of what you read in MSDS type literature is overstated. That is a real problem, because some is not and you have to be an expert to figure out which boojums are real boojums.

Lars: "Misleading" How, he asked about "Malaria" ?

"Am not sure about the other species of Plasmodium that affect humans, but as I recall, they're human-specific as well"

Look at plasmodium knowlesi (from Baboons) for instance.

Come off it cs, the context was malaria in people.

You don't have to understand the mechanisms of resistance to know that spraying DDT can and has lead to resistance. I think this was first observed in the late 40s. I don't think that all pyrethroid resistance also gives DDT resistance -- else South Africa's switch from pyrethroids to DDT would have been ineffective.

Are you seriously disputing the fact that reducing malaria infection rates with drugs reduces the malaria infection rate?

Tim: "Come off it cs, the context was malaria in people" Ok, granted. I thought the questioner might be interested to know a little more about the disease is all.

"You don't have to understand the mechanisms of resistance to know that spraying DDT can and has lead to resistance"

Yes, but I'm not disputing this. I was disputing the argument that ag. DDT bans have saved lives (due to slowing DDT resistance) and saying this this might or might not be right, as the bans lead to farmers using other insecticides that increase DDT resistance. Personally I don't think it is correct to state this, it is simply not defensible, IMO it could likely be wrong.

"I don't think that all pyrethroid resistance also gives DDT resistance — else South Africa's switch from pyrethroids to DDT would have been ineffective."

Not all, I believe most of the A. Funestus pyrethroid resistance in South Africa (and Mozambique) was metabolic due to elevated MFO's. The KDR is where the cross-resistances between them lie.

"Are you seriously disputing the fact that reducing malaria infection rates with drugs reduces the malaria infection rate?"

I am saying that preventing infection rates with antimalarials is backwards,
just as a strategy to prevent HIV infections through "cocktails" would be backwards. (although both would be effective to some degree) As far as South Africa the newer antimalarials would have had more of an effect on mortality, not infection rate. And wrt deltamethrin in Western Style homes, western style homes have window screens, the deltamethrin would be pretty much irrelevant in that case. The relevant contributor was DDT.
To answer your question more directly, no.

I should probably clarify something, I'm not in bed with DDT, I just don't like to see such a cost effective tool being undersold and vilified (by that I don't mean vilified on this blog, just a more general rant) to such a high degree.

Mr Lambert,

Writing in the Lancet (2000), Roberts, Manguin and Mouchet argue that it was misguided environmental concerns and not resistance that prompted the move away from DDT:

Resistance of Anopheles spp mosquitoes to DDT is not a major barrier to the continued use of DDT for malaria control (ie, where DDT is still effective, it should be used). Resistance slowly appeared in the 1960s in response to intensive agricultural uses of DDT, especially in cotton production. The current distribution of DDT resistance among malaria vectors covers limited regions located in West Africa (A gambiae), southwest Asia (Iran, Pakistan, India, Sri Lanka; A culicifacies), Greece (A sacharovi), Egypt (A pharoensis), Central America (A albimanus), and a small area of Colombia in South America (A darlingi).

Claims of risks of DDT to human health and the environment have not been confirmed by replicated scientific inquiry. This is all the more remarkable given that DDT has been used for malaria control for almost 55 years. According to Curtis and Lines, toxicity of DDT in human beings and effects on the environment are questionable and require further investigation.

Since the early 1970s, DDT has been banned in industrialised countries and the interdiction was gradually extended to malarious countries. The bans occurred in response to continuous international and national pressures to eliminate DDT because of environmental concerns.

But, what would these guys know, right?

J F Beck: Roberts's views are well-known amongst those of us who have studied this issue. He just gave some remarkably deceptive testimony before Senator Inhofe's Environment and Public Works Committee a week ago (along with Michael Crichton).

As for DDT's effects on the environment, even the Malaria Foundation International (that provided your link to the Lancet article), which fought for the continued use of DDT against malaria, admits on its FAQ page (http://www.malaria.org/DDTcosts.html) about DDT that DDT has detrimental environmental effects when if its use is not restricted to indoors: "DDT is hazardous to certain wildlife species and should not be used outdoors or in natural areas."

Here is what that same page says about resistance to DDT:

"Are There Regions Where DDT No Longer Works? Anopheles mosquitoes are physiologically resistant to DDT in some regions, and thus DDT is not effective in these areas. Current insecticide resistance test data should be used when planning malaria control efforts. Much resistance test data is 15-30 years old, and current resistance test data should be gathered.

Are There Regions where DDT is Still Effective?In some regions. the vectors of malaria are still susceptible to DDT, and the compound remains effective in blocking malaria transmission. An example is control of Anopheles funestus in South Africa."

And remember, this is from an organization who fights for the use of DDT against malaria (although one who seems to be genuinely interested in fighting malaria and not just a knee-jerk supporter of DDT for the hell of it...and because of strong dislike for government regulation on almost any environmental or health issue...like the folks at Africa Fighting Malaria).

"Resistance slowly appeared in the 1960s in response to intensive agricultural uses of DDT..."

... which is what is being advised against doing! The general so-called 'ban' on DDT applies to agricultural use, and is intended to slow the development of DDT resistance.

Over and over again, I read that the need for the ban on agricultural spraying is to slow the development of resistance and to keep DDT out of the food chain. Both seem quite reasonable.

"toxicity of DDT in human beings and effects on the environment are questionable and require further investigation."

Not exactly an endorsement of ingesting DDT. Following the principle of unintended consequences, one should proceed carefully before introducing something new into the environment, let alone our food, no?

I haven't read the study, but the Lancet excerpt posted doesn't lend support for indiscriminate spraying of DDT.

DDT has a place, but should be used carefully.

Joel Shore and Mark, Tim Lambert claims DDT use - we're talking about indoor residual spraying here - was curtailed due to resistance. As the Roberts et all Lancet piece indicates, not everyone accepts this.

"I would stay away from claiming DDT causes cancer. If so, it is an extremely weak carcinogen, and much of what you read in MSDS type literature is overstated. That is a real problem, because some is not and you have to be an expert to figure out which boojums are real boojums."
In summary, it would be wise to avoid ingestion of DDT until proved otherwise.

Cost of lambdacyhalothrin-treated nets per malaria case prevented: $1.54 US. Cost of DDT spraying per malaria case prevented: $1.87 US. (21% more)
-Kamolratanakul, P., P. Butraporn, M. Prasitisuk, C. Prasittisuk, and K. Indaratna. "Cost-effectiveness and sustainability of lambdacyhalothrin-treated mosquito nets in comparison to DDT spraying for malaria control in western Thailand." American Journal of Tropical Medicine and Hygiene 2001, 65(4), 279-84.

Malarial vector mosquitoes have become resistant to DDT and HCH in most of India.
- Sharma, V.P. Current scenario of malaria in India. Parasitology 41: 349-53, 1999.

DDT is obsolete for malarial prevention, not only owing to concerns over its toxicity, but because it is losing its effectiveness. Use for agriculture was banned in India in 1989, and use for malaria has been declining. Food supplies and eggshells of large predator birds still show high DDT levels. Use of DDT in urban areas in India has halted completely.
-Agarwal, Ravi. No Future in DDT: A case study of India. Pesticide Safety News, May 2001.

For what it's worth, by the way, it is pretty daft to suggest that checking for DDT residues would impose "an impossible burden on a poor country". Uganda already exports a lot of food to the EU, and it already uses pesticides, and as a result of these two facts, it already has an inspection regime to ensure that its food exports don't have excessive pesticide residues on them (imagine what would happen if you presented Tesco with a container of lettuce that had pesticides all over it). Testing for DDT would be a minor addition.

Z - while interesting that cost comparison (between netting and DDT spraying is potentially misleading.)

For one thing, it would be more useful to compare netting treated with DDT against netting treated with a different insecticide or spraying DDT versus spraying another insecticide.

There are also questions of effectiveness (as opposed to cost-effectiveness) if, for example, netting prevented 80% of potential malaria cases and spraying prevented 90% then you'd probably opt for spraying even if it were more expensive.

I'd need to read the whole article to get a better understanding of the relative benefits of the two approaches.

For example, the logistics of getting spraying teams into remote areas is probably more daunting than getting nets to those areas but spraying is a one-off operation whereas getting people to use nets requires education and depends on ongoing compliance.

"Tim Lambert claims DDT use - we're talking about indoor residual spraying here - was curtailed due to resistance."

He has? Where? I read Tim mention that widespread use in places like Sri Lanka have caused wide-spread resistance to DDT, but don't recall him claiming that limited targeted use has caused widespread resistance.

Got a url and a quote? I'm not arguing otherwise, but I don't recall such a claim. Tim seems to be arguing against going back to spraying the stuff all over the place, and points out that there are alternatives which work.

15: Joel, "Roberts's views are well-known amongst those of us who have studied this issue." Can you elaborate?

16: Mark, " which is what is being advised against doing! The general so-called 'ban' on DDT applies to agricultural use, and is intended to slow the development of DDT resistance" this is most certainly not the intended reason, even the WHO identifies the reasons for leaning against even DDT for IRS as being due to environmental and political concerns. Slowing vector resistance might be a side effect, however, as I stated previously, that might not even be the actual result.

"DDT has a place, but should be used carefully"

No qualms there, but the operative word is carefully. IMO, it is better to err in the almost certainty of reducing infection rates and mortality than it is to err on the side of unknown/unquantified possible negative effects.

17: JF Beck: Further, Lambert hasn't demonstrated "widespread" resistance. (in fairness to him, it is simply because widespread resistance hasn't exactly emerged)

18: z: "In summary, it would be wise to avoid ingestion of DDT until proved otherwise"

This would have been a good call in the early 1950s. You might want to have a look at:
[The effect of known repeated oral doses of chlorophenothane (DDT) in man. Hayes, WJ J Am Med Assoc. 1956 Oct 27;162(9):890-7 ] or perhaps [Laws ER Jr, Curley A, Biros FJ. Men with intensive occupational
exposure to DDT. Arch Environ Health 1967;15:766-775 ]
or even [Silinskas KC, Okey AB. Aflatoxins inhibited by DDT in diet. J Natl
Cancer Inst 1975;55:653-657 ][McLean AE, McLean E. Diet and toxicity. Br Med Bull 1969;25:278-281] for evidence of DDT's anticarcinogenic effects.

19: z: This seems rather peculiar, I'll have to read the full article later.
20: z: First cite agreeable, I don't think anyone is disputing this. Second cite? I really can't take that seriously.

21: dsquared, I have no idea what the additional costs might be, probably depends on what the Ugandan Export Promotion Board/EU decides on as far as certificates/analysis and whatnot.

22: Ian, I agree. Like I said, I need to read it myself.

23: Mark, scroll up to the top of this page and you see, "Nowhere is mentioned the main reason why **anti-malaria** programs have shifted away from DDT—the widespread development of resistance to DDT by mosquitoes" (emphasis added)

cs, Roberts is obviously downplaying the extent of resistance, but even on his list it's pretty widespread. For a more complete list see [here](http://www.pesticideresistance.org/DB/pesticide_profile.php?pageNum_rst…)

The agricultural use of DDT has caused hundreds of millions of cases of malaria.

Well, I've yet to see the study or studies which convinced all the bleeding heart industrialists and tree-rapers of the unbeatable cost-effectiveness of DDT to which they refer in such a frequent and offhand way. In fact, in my whirlwind immersion in the literature, it has become quite clear that this type of quantitative information is sorely lacking, as indicated in part by the mention in several reviews that this type of quantitative information is sorely lacking. It seems also clear that the relative and absolute cost-effectiveness of various treatments will vary enormously with location, accessibility, degree of urbanization, species of mosquito, various resistances of the mosquito, availability of medical treatment in the area, degree of compliance of the population, etc. etc. etc. So, without further ado,

Review article: The evidence base on the cost-effectiveness of malaria control measures in Africa
CA GOODMAN AND AJ MILLS
HEALTH POLICY AND PLANNING; 14(4): 301-312 1999
This review assesses the range and quality of the evidence base on the cost-effectiveness of malaria prevention and treatment in sub-Saharan Africa. Fourteen studies are reviewed, covering insecticide-treated nets, residual spraying, chemoprophylaxis for children, chemoprophylaxis or intermittent treatment for pregnant women, a hypothetical vaccine, and changing the first line drug for treatment. The available evidence provides some guidance to decision-makers. However, the potential to inform policy debates is limited by the gross lack of information on the costs and effects of many interventions, the very small number of cost effectiveness analyses available, the lack of evidence on the costs and effects of packages of measures, and the problems in generalizing or comparing studies that relate to specific settings and use different methodologies and outcome measures.
...
Residual spraying
Residual house spraying involves the treating of all interior walls and ceilings with an insecticide, and is effective against mosquitoes that favour indoor resting before or after feeding. Advocated as the mainstay of malaria eradication programmes in the late 1950s and 1960s, it remains a major component
of control programmes in southern African states, though many countries have abandoned or curtailed their spraying activities due to disillusionment over the failure to achieve eradication, concerns over the safety and environmental impact, and administrative, managerial and financial constraints on implementation.
Two cost-effectiveness estimates are available. Firstly, data from a trial conducted in Garki, Nigeria were used by Barlow and Grobar...
Secondly, Walsh and Warren provided an estimate of the cost per DA of residual spraying.... Neither study can therefore be considered an accurate estimate of the cost-effectiveness of spraying. Moreover, the estimates may not be good predictors of cost-effectiveness in current programmes.

MEXICO: Relying on a range of effective and affordable chemical and non-chemical strategies, Mexico has been so successful that its DDT manufacturing plant has ceased production due to lack of demand. The Director of Mexico's malaria control program declared that it is 25 percent cheaper for Mexico to spray a house with other chemicals--synthetic pyrethroids--than with DDT.

Which brings us back to the other unanswered question: What DDT ban?:
USAID Support for Malaria Control in Countries Using DDT
Contrary to popular belief, USAID does not "ban" the use of DDT in its malaria control programs. From a purely technical point of view in terms of effective methods of addressing malaria, USAID and others have not seen DDT as a high priority component of malaria programs for practical reasons. In many cases, indoor residual spraying of DDT, or any other insecticide, is not cost-effective and is very difficult to maintain. In most countries in Africa where USAID provides support to malaria control programs, it has been judged more cost-effective and appropriate to put US government funds into preventing malaria through insecticide-treated nets, which are every bit as effective in preventing malaria and more feasible in countries that do not have existing, strong indoor spraying programs.

Other cost effective and fun malaria fighting:

Mosquitos with Glowing Testicles Fight Malaria
From The Independent:
By Katy Guest
09 October 2005
British scientists have made a breakthrough in the control of malaria: by creating mosquitoes with fluorescent testicles.
...
http://blighty.multiply.com/journal/item/655

Tim: I've visited the site before. What's missing is the quantified per cent survival rate of the resistant species as suggested by the research being cited. There's a lot of research being cited, so I suppose the onus is on you to go through it all to defend your extraordinary claim. :) Locations of the resistant vectors are also key. (ie, the A. Funestus resistance reported in Mali in 1986, had no effect on the 0 per cent DDT resistance found in South Africa ~2000)

"The agricultural use of DDT has caused hundreds of millions of cases of malaria."

WOW! This is a tremendously fantastic claim.

26: z, as far as cost benefit analyses, check some of the comments on other DDT posts on this blog, I think there have been some discussed.
IIRC, in SSA, with imported DDT you can cover an average sized home for about US$1.00 for ~9 months. (much of the cost is transportation so it'd obviously be cheaper if it were allowed to be synthesized in said countries) As of a few years ago, the cost of an ITN was ~US$2.00 with the insecticide lasting ~2 years. Dual-insecticide treated nets might be available commercially by now. Of course, net costs can be reduced if made locally as well.

The first cite, yeah, there is certainly not enough research into cost effectiveness, WHO has hardly done any research on it themselves, and when they did, the results were basically "there is not enough research into cost effectiveness".

The second cite, unfortunately I can't seem to access the pdf, but what you quoted is misleading. The major reason for Mexico's closing of the plant was NAFTA's North American environment commission (CEC)'s "North American Regional Action Plan on DDT, Task Force on DDT and Chlordane" which in 1996 called for the elimination of DDT manufacture and of DDT for use in vector control in Mexico within 10 years. The third cite looks to be apologetics for a poorly thought out policy.

27: z, now *this* is interesting. Sounds similar to the elimination of the TseTse fly on Zanzibar island. I've seen quite a few GMO type propositions for anopheles control, but this is certainly the most humorous. I have a lot of hope for efforts like this, but wonder if the fear campaigns might hamper testing.

"27: z, now this is interesting. Sounds similar to the elimination of the TseTse fly on Zanzibar island. I've seen quite a few GMO type propositions for anopheles control, but this is certainly the most humorous. I have a lot of hope for efforts like this, but wonder if the fear campaigns might hamper testing."

Oddly enough, the very night previous to seeing that news item, I dreamt of praying mantises with bright blue genital areas (somewhat fuzzy in detail, me not having a very precise concept of what the actual genital area of a praying mantis looks like, exactly).

To understand the DDT issue it is important to look at the bigger political picture. The modern environmental movement has been a grassroots political campaign that defeated political and philosophical conservatives and their corporate allies. Environmentalists did this using scientific facts in an open democratic process.

Conservative/corporations regrouped and fought back using dirty political tactics. A favorite trick is to portray enviros as dislikable extremists. These tactics use false and misleading tactics and can be seen in the DDT debate. The goal is to portray enviros as elitist whites who misuse science to impose their pagan/nature-first beliefs on the world and refuse to see or don't care about all the suffering they are causing on the poor nonwhite third world.

For some facts:

Are the enviros stopping the use of DDT?
NY Times columnist Kristof (Time to Spray NYT) contacted WWF and Greenpeace and was surprised when they said they did not oppose the use of DDT if it was used carefully.

Did environmentalists force the WHO to curtail the use of DDT?
The U.S. National Academy of Science reported:
"In 1955, the World Health Organization (WHO) called for the global eradication of malaria through the use of DDT. However, the mosquitoes that carry the disease soon developed resistance to DDT, and in 1976 WHO shifted its goal from eradication to control"
The Resistance Phenomenon in Microbes and Infectious Disease Vectors: Implications for Human Health and Strategies for Containment -- Workshop Summary (2003)
http://books.nap.edu/books/0309088542/html/R1.html

Is resistance to DDT a real problem?
The Academy in another report noted that resistant populations of insects are now more common then populations that are fully susceptible to pesticides.
"Unquestionably the phenomenon of resistance poses a serious obstacle to efforts to increase agricultural production and to reduce or eliminate the threat of vector-borne diseases."
Pesticide Resistance: Strategies and Tactics for Management (1986)
http://books.nap.edu/books/0309036275/html/R1.html

Joseph: Pretty broad brush stuff, are you replying to Tim's post or?

z: I think I speak for the whole platoon when I ask, please don't post about your dreams again. :)