Is there a de facto DDT ban?

One of your earlier

posts on the myth of the DDT ban had to do with Eritrea's success in reducing malaria through use of insecticide treated nets and narrowly targeted indoor spraying.

As it happens, I share an office with an engineer from Eritrea. I asked him about the efforts against malaria there, and he referred me to

another site telling much the same story:

Eritrea has short rain and limited water bodies and we can easily control them. We can never be compared with neighboring countries like Kenya and Uganda, which have long rainy seasons. So this environmental management or water sanitation is very important. In addition, we spray insecticides in certain selective areas to kill the adult mosquitoes indoor. The indoor insecticides we use are DDT and malatine. This is important because DDT in particular is not degradable and it is well taken care of. It is only used in selective areas of Gash Barka and Debub since we are very conscious of the dangers of using DDT.

Eritrea's anti-malarial effort has been so effective precisely because its managers recognize the need for a broad, carefully planned attack on the parasite and its vector, use the best weapons available, and aim before they shoot.

In contrast, Roger Bate & Co. advocate the more or less indiscriminate use of DDT against malaria, and claim that the WHO has somehow been hoodwinked by environmentalists into giving up the best available weapon against the disease. Bate is dead wrong. In fact, WHO and its predecessor organizations were enthusiastic cheerleaders for widespread, heavy use of DDT anywhere malaria was found -- until rapid development of insecticide resistance in the 1950s scared the hell out of them.

WHO learned from experience. It's a shame Roger Bate hasn't managed it yet.

ITYM "exports" not "experts".

Thanks, I fixed it.

An aside: I wonder if the supporters of the "De Facto ban" theory would like to claim that the US government's policy of not funding aid agencies which conduct or recommend abortions amounts to a de facto ban on abortion?

The linked ReliefWeb article starts off:

The European Union has cautioned Uganda against the use of an organic pollutant to control malaria, commonly known as DDT, warning that its use could pose dire consequences for exports to the European market.

Odd wording, no?

The article also notes the following threat from the EU head of delegation in Uganda, Sigurd Illing:

"We just made a general warning that we want to see that all considerations are made before the spraying. Uganda also needs to decide why it should use DDT - is there no other alternative - because there could be many implications with DDT."

Followed by the clincher:

The government has indicated its readiness to use residual spraying in people's homes to reduce the incidence of malaria, but environmentalists have argued against the move.

There's a determined effort to prevent DDT use, damn the collateral damage.

DDT is not de facto banned for outdoor use, it is about as banned as you can get for outdoor use. So areas that might be able to effectively use DDT outdoors to increase crop production and slow malaria do not have that option. Never mind that DDT has never been proven a carcinogen and that DDE might even reduce the occurrences of certain types of cancer.

Then throw into the mix 4 decades of environmentalists trying to outright ban DDT on flawed science and you start to see why there is so much backlash. And it isn't like the environmentalists have learned about bad science. We have UNEP in 2000, Stockholm in 2001, the WWF never ending attempts at banning, and the hundreds of other environmental organizations that never give up the goal of a total ban on DDT.

So while there are only legal bans on DDT for some uses, the fact that DDT costs more because factories have to plan on being shut down tomorrow, that countries have to be careful that farmers' independent use of DDT doesn't get their country's agricultural products banned from the EU (never mind the added cost of testing exports for DDT), and finally that lining up contracts for purchasing DDT takes a long time and must be approved by those would like to see DDT banned adding delays and costs, and you might be able to see why some would call that a de facto ban.

jet, using DDT outdoors is a very effective means of creating DDT resistant mosquitoes. If you actually cared about saving lives from malaria you would support a ban on the outside use of DDT.

1. The EU warning is not a ban in the strict sense if the term, rather it a veiled threat. It is a strong disuader not to use it. Language as we all know does not have to be explicit when an implicit threat will do just nicely.

Tim, I don't understand the logic of your argument.

1. Why do you find it OK to spray indoors and not OK to do so outside. I ask this because you argue the mosquito population develops resistance to it. Are you suggesting "in-house" mosquitoes are less resistant than the outdoor population? Really? If not then liberal outside use would be just as effective as in-house. Right?
2. If the Mos. population develops hard resistance then indoor use ought to be useless. Right? You don't address this gap.
3. If DDT is so dangerous, why is it that you don't suggest indoor use poses a danger?

4.With malaria killing millions of people around the world resistance or no resistance, wouldn't you want to throw the "kitchen sink" at this deadly problem?

Pessimist,

Indoor use only exposes a small subset of mosquitoes to the chemical, which will not breed resistance. By hitting most of a breeding population, outdoor use puts pressure on the population to develop resistance.

This point answers 2 and 4 as well--that indoor use only will never (or only very slowly) become ineffective, while outdoor use will quickly make both indoor and outdoor useless.

Over-simplifying a bit, a way to think about it is that there are limited number of mosquitoes that can be killed with DDT: obviously killing them where they do the most harm (in people's home) is better.

As far as 3, I haven't seen Tim call DDT dangerous anywhere. Based on his posts, his major concern is resistance, and of course environmental effects worry many people. In that sense, the indoor/outdoor split is also perfectly logical. Volume makes a big difference. There's not really a problem with selling people Liquid Plumber for home use, but we don't let industry dump sodium hydroxide down the drain with quite the same abandon.

Indoor use also exposes the insects to much larger doses of DDT, with leads them to them just dying. Spraying outdoors can lead to smaller doses, which kill the less hardy mosquitos, and allows the more hardy mosquitos to survive. This leads to resistance increasing, but Intelligent Design tells me that it doesn't.

With malaria killing millions of people around the world resistance or no resistance, wouldn't you want to throw the "kitchen sink" at this deadly problem?

Wow.

No, because 'throwing the kitchen sink' at the problem is very likely to cause DDT-resistant mosquitoes.

I say again: 'throwing the kitchen sink' at the problem is very likely to cause DDT-resistant mosquitoes.

Let me repeat: 'throwing the kitchen sink' at the problem is very likely to cause DDT-resistant mosquitoes.

One last time: 'throwing the kitchen sink' at the problem is very likely to cause DDT-resistant mosquitoes.

Judicious use of DDT is much less likely to produce resistance.

Also, remember that the mosquito is a vector. There's another critter that actually causes malaria. You may want to think about quinones and resistance there too when problem-solving by kitchen sinking.

HTH,

ÐanØ

We have here an opportunity to correct some of the most common misconceptions about DDT, mosquitoes and malaria. For example,

With malaria killing millions of people around the world resistance or no resistance, wouldn't you want to throw the "kitchen sink" at this deadly problem?

That was exactly the approach taken by public health officials in the late 1940s and early 1950s. There were great early successes against Anopheles in areas where the geography and the habits of the insect made eradication possible. This led to the optimistic view that malaria could be eliminated world-wide, followed by ambitious eradication campaigns in many countries. That was followed by shock and dismay when DDT-resistant mosquito species started to appear. It is no accident that the first observation of a resistant species was in Greece, where DDT application had been extremely heavy, and the terrain made it almost impossible to assure 100% coverage.

Are you suggesting "in-house" mosquitoes are less resistant than the outdoor population? Really? If not then liberal outside use would be just as effective as in-house. Right?

Excellent question. Indoor spraying is more effective against malaria than outdoor spraying because it is targeted at breaking the chain of transmission. Only the female mosquito bites, and then only when she needs a blood meal to nourish an upcoming brood of eggs. If she can be killed at that point, or prevented from biting an infected person, the reservoir of malaria parasites can be reduced to low levels -- ideally, to zero. Spraying inside walls and using insecticide-treated nets are the most effective ways to break that link in the chain. Spraying all mosquitoes outdoors, all year round, doesn't kill them all (and a few mosquitoes are just as good as a whole bunch in spreading malaria). By causing resistance, this destroys the value of the insecticide where it would do some good.

Then throw into the mix 4 decades of environmentalists trying to outright ban DDT on flawed science and you start to see why there is so much backlash.

In fact, efforts to restrict the use of DDT over the past four decades have been based very much on the best science available, and on the hard-won lessons of the struggle against malaria. As we have seen, blanket application of DDT is a recipe for resistance. Its stability and persistence in the environment are actually advantageous when it is used for indoor spraying, but cause long-lasting harm to wildlife when it is used indiscriminately. The restrictions that have been placed on the use of DDT were (and are) amply justified on the basis of the best information available; politically motivated attempts to paint this as "flawed science" are not just mistaken, but irresponsible.

Jre:

"As we have seen, blanket application of DDT is a recipe for resistance".

Isn't that like telling a soldier not to shoot because he may just miss this enemy?
In war precision is not the name of the game: it's firepower. Same with killing deadly mozzies.
So what, if down the road, mozzies develop resistance? They may well do and I am not disputing that. But even if the kill rate falls because of heavy use, that's not a reason to stop using effective but maybe (in future) less effective fire power.
In clear and present danger you deal with a problem with what you have and worry about the consequences of indiscriminate use down the road.

Sorry, but you're a lot of these arguments don't wash in my book.

I wouldn't want to be telling grieving parents their kids died of malaria, which may? have been preventable. But they couldn't use it because mozzies develop a resistance to it down the road and the local magpie population may produce soft eggs. Live kids and soft magpie eggs are far better than dead kids and normal magpie eggs in my book.

I don't really know a great deal about this issue other than what I have read on Tim's and other sites. What I see is a lot of he said this and he said that type of argument. Most of us don't have the time or inclination to do the research ourselves about this very important issue.

As I see it, if Tim's assertions are right, well and good, which therefore makes right wingers either liars or ignorant and therefore deserve savaging. However if the anti-green assertions are correct then I can only say that we ought to judge the people who stopped the use of DDT as mass murderers.

I suggest there is an easy way of figuring out what has gone on.

1. Find out what is the annual production of DDT and like agents for the last 40-50 years.
2. If production of DDT and like agents has fallen ask why.
3. Find out cost of production of these chemicals (what has happened historically to the C of P) and ask if there are any legal impediments to its production (like rules and regulation). In other words can I set up a DDT production plant down the road as easy as I could as any other chemical plant?
4. Find out how easy it is to purchase DDT (in other words can I go to the local hardware in Deli and buy myself a few gallons with no questions asked.
5. Ask the firm, which Tim, said he found selling DDT, what do we need to do to buy it.
6. Ask where can't you buy the stuff and why?

In other words the proof is in the pudding, so to speak.

I am in no way siding with anyone on this issue. I would just like to know the facts.

One last thing I forgot to add....

Finding a firm's website selling DDT over the web doesn't wash as an argument that widespread use of DDT was not banned/prevented in my book and here's why.

Legitimate poppy production does go on. There is/was a poppy farm around in the 80's legally sanctioned by the Government to produce poppies to make heroin or like substances.

You can see where this example leads to without further explanation.

So, pessimist, what do you tell grieving parents whose child died from malaria because indiscriminate use of DDT created resistance? This isn't a theoretical question. In 1975 there were 400,000 case of malaria in Sri Lanka despite extensive DDT spraying, whereas with a similar amount of spraying before the mosquitoes were resistant, there were hardly any cases.

Pessimist, you do not yet understand why insecticide resistance in mosquitoes is such a bad thing. You say,

But even if the kill rate falls because of heavy use, that's not a reason to stop using effective but maybe (in future) less effective fire power.

Yes, it is. The reason why is inherent in the mechanics of malaria transmission and the fecundity of the mosquito.

The Southwest corner of Ceylon (now Sri Lanka) is much wetter than the rest of the island, and historically has had low rates of malaria in comparison, because the heavy rains wash away the mosquito eggs. In 1934, an unusual drought made conditions much better for Anopheles reproduction, and in October the hospitals started to see a large number of malaria cases. By December, half a million Ceylonese (or 10% of the population) were sick with the disease. The epidemic continued throughout 1935, ultimately infecting 1/3 of the population and killing 80,000. Health workers were stunned by the suddenness and ferocity of the epidemic, and some set out to explain it. The mystery was solved by Colonel Clifford Gill of the Indian Medical Service, who observed that the disease came in waves four weeks apart, which happens to be the total time of incubation for the Plasmodium parasite and the mosquito. George MacDonald later developed a mathematical model that demonstrated neatly how an epidemic of malaria can snowball. He calculated that the Ceylon epidemic could be explained by a 5.3x increase in mosquito numbers, or a slight increase in mosquito longevity.

"So - " you say, "all we need to do, then, is kill four out of five of the mozzies, and we're back where we started, right?" If only. The other problem is that mozzies are just so goddamn fertile. One female mosquito, depending on her species and breeding conditions, can lay 50 to 500 eggs in her first brood, and almost as many in each of the eight or ten more broods she will lay before she dies. Five generations later, she has 20 million descendants. In consequence, it doesn't do any good to kill 99% of the mosquitoes, because the survivors can quickly make up the loss. And -- here's the nasty part -- if those 1% surviving happen to be the most DDT-resistant mozzies in the population, then each of them will have given rise to 20 million DDT-resistant mozzies in five generations. That, in a nutshell, is why blanket spraying is the epidemiological equivalent of shooting yourself in the foot.

But is there any hope, then, of controlling malaria? Absolutely, because we don't need to kill all the mozzies (which is impossible, anyway) -- we just need to keep them from transmitting malaria! And that we can do, by keeping them from biting infected people and carrying the parasite to uninfected people. We do that by screening blood samples for malaria, administering antimalarial drugs to kill the parasite, equipping people with insecticide-treated nets, and spraying the inside walls of their homes with insecticides (including DDT) and repellents to kill the insects or drive them away. As has been proven time and again, that approach works! The line "it's all the fault of those damn environmentalists for trying to ban DDT" taken by many strikes me as smugly ignorant. If we were to act on that point of view, by returning to using DDT in a dangerously counterproductive way, that would be a victory of ideology over public health.

Isn't that like telling a soldier not to shoot because he may just miss this enemy?

It's nothing like that. If you like military analogies, consider the use of broken codes in WWII: the allies couldn't take advantage of them indiscriminately, since that would tip the Germans off. They had to save application for critical moments.

I guarantee you a lot of preventable deaths took place. And yet, there isn't really any argument that the general strategy was flawed--until now, I guess, with your "think of the children" appeal.

Live kids and soft magpie eggs are far better than dead kids and normal magpie eggs in my book.

Yes, now it's clear you don't understand the discussion. Despite a half-dozen explanations on the human cost of inducing resistance, you seem to be replying to some other, different argument made by some hypothetical environmentalists about magpie eggs.

The choice presented here is few dead kids (indoor spraying) or many dead kids (outdoor spraying). If you don't buy this, you could argue that outdoor spraying doesn't cause significant resistance, or that indoor spraying is totally ineffective. Such arguments would seem to be false, but they'd at least be relevant to the discussion.

I neglected to credit my source:

Gordon Harrison,

Mosquitoes, Malaria and Man,
E. P. Dutton, 1978, pp. 141-142 and 205-207

Now out of print, unfortunately, but find a used copy if you can. Mine came from Florida, and arrived with a bonus -- the biggest millipede I've ever seen, dry and squashed flat between the pages.

Tim:
I take your point.
However, I would also find it hard to tell people we can't use DDT today because of resistance problems down the road.

This piece reminds me of the health authorities concerns with the over use of antibiotics. Of course resistance to abs runs at a slower pace than mozzies to DDT. However the argument also remains the same, in that we do not stop using a medication because it may cause a problem with resistance in the future. I ought to know, because of the difficulty of eradicating sinusitis I am on my 12th strip of Antibiotic pills this year. It scares the sh.. out of me about resistance problems down the road. But hey, I gotta get rid to this dreaded illness now.

The thing, which really strikes me about this story, is why are we arguing about the use of DDT: a chemical that is 40 years old. In other words why has technological progress stopped dead in its tracks in R&D that could find an agent that would zap super-mozzies. It's not as though there wouldn't be any money in it as I am sure there would be.

My hunch, and I hope I am wrong, is that no self-respecting firm or group of scientific geeks would not go near this area because they are frightened by an environmentalist tsunami hitting them at 500 kph. Again, I am only speculating here, but surely there is enough brain power around that find other more deadly agents that would combat these hellish insects that are new and therefore resistant-free.

I hope I am wrong in my hunch.

pessemist,

DDT is 60 years old and was developed under the auspices of the war dept during WWII. Entomologists and malariologists involved in the development and use of this military tool warned of the unintended negative effects of widespread civilian use.

See: Russell, Edmund P. (1999). The Strange Career of DDT: Experts, federal capacity, and environmentalism in WWII. Technology and Culture, 770-796.

Pessimist,

Your eagerness to blame those damned environmentalists for something really knows no bounds, doesn't it?

Iain:

"Your eagerness to blame those damned environmentalists for something really knows no bounds, doesn't it"?

No, Iain. And no again. I have beef with environmentalists. I am just looking for anwsers. But I do have a beef with blatent disregard for human life. I also have a beef with dishonesty.

Tim's great work in exposing Lott as a fraud deserves the Pulitzer prize. No kidding.

I do resent your attack though for no other reason that it doesn't lead anywhere.

My question, I think is reasonable. Why is it we are still talking about a 50/60m year old chemical when it should be have been superseded by something more effective? Has R&D been hampered inthis area? I don't know the anwsers to these questions. Do you?

Pessimist,

Technological progress has not been "stopped in its tracks" - there are a wide range of other pesticides which can be and are used for mosquito control.

Unfortunately admitting that would deprive the spreaders of the "DDT ban" myth of their millions of alleged victims.

The other insecticides are generally more expensive than DDT but have other advantages (i.e. they don't bio-accumulate).

You mention antibiotic resistance and that's actually a pretty good analogy for DDT resistance.

There's an antibiotic known as methycilin. Its use is restricted to treating infections which are resistant to other antibiotics. If it were used More generally, bacteria would evolve resistance to it as well. (There's already a methycilin strain of Staphylococcus which is extremely difficult to treat.)

Similarly, it makes sense to limit insects' exposure to DDT and the development of Resistance by using it in the most critical and most effective way - netting and in-house spraying. You probably need (I'm guessing here) 10 times as much DDT in outdoor spraying to get the same benefit as using a litre for in-door spraying.

Similarly it makes sense to use a variety of insecticides - use DDT for several years then switch to malathion for a few years then switch to dieldrin then back to DDT - that's because there's usually a cost to the insect of developing immunity to a particular insecticide. They need to produce special enzymes to neutralise the insecticide.

Take away the exposure and immunity will gradual decline over successive generations especially if there's now selective pressure to evolve immunity to a second insecticide - then you hit them with the first insecticide again.

So, you see, even if claims that DDT is in some aspects superior to some other insecticides is true, a rotational system using DDT and those other insecticides may be superior to continuous DDT use.

There's a danger in all this that we lose sight of the bigger picture - which is the urgent need to reduce deaths from malaria.

Malaria was virtually eliminated from Europe and the continental US by the 1930's - before DDT or other insecticides were available. So it is possible to eliminate malaria without the use of insecticides.

Similarly, Africa accounts for around 50% of new malaria cases each year but 90% of malaria deaths. I've heard suggestions that there's a different and more deadly strain of malaria in Africa but I suspect the poor state of the health systems in most African states also contributes to this.

So rather than pushing the DDT barrow people who're genuinely concerned about saving lives might want to consider practical actions like donating to private charities seeking to develop new malaria treatments or lobbying western governments to promote free trade and democracy in Africa.

(Free markets and free elections don't guarantee economic growth or a reduction in corruption and government inefficiency but they do make them more likely.)

Ian Gould

I just thought of something. I recall my grandparents freely spraying with DDT in the 50's and 60's. It was readily available at the local hardware store. I also remember local councils using it around the streets, particularly around storm water traps.

I am going to do a few things to prove or dispute whether DDT is banned or not.

1. I am going to go to Home Depot and see if I can buy DDT. If not, I will ask why.
2. I am going to contact my local council and ask if I can spray my garden and surrounding area with DDT.
3. I am going to call the state and federal Health departments and ask how I can get my hands on DDT.

If Tim doesn't think it is banned, maybe he could tell me where in Australia I can buy a few gallons of the stuff.

Now I am not attempting to argue here about the potential dangers regarding it's use/ resistance etc. I am trying, like Tim, to determine whether the stuff is bendy or not. I will let everyone know the answers in the next week or so when I have time. That is unless someone already has those answers.

Pessimist,

You are confusing "banned" with "readily available". Simply because you cannot walk into your local hardware store and buy a few litres of DDT does not mean that it is banned. It merely means that its use is regulated, regulated in the same way that prescription drugs are. You can hardly make the claim that antibiotics are banned simply because you cannot get them without your doctor giving you a prescription.

Ian Gould:

1. I called my local council and spoke to the health department. After I asked a dumbstruck woman I wanted to spray DDT around the house and garden she referred me to the state health authority, as she believed DDT was not an allowable substance. She said it caused cancer and therefore could not be used. I informed her that it was the first time I had ever heard that cancer was a cancer agent.
2. I then called the State Health Department. They told me DDT was not allowed to be used in Australia, as it was not on the APVMA register of pesticide agents. Referred to www.apvma.gov.au. I was warned if anyone was caught using DDT they would prosecuted, fined and most probably spend time in the can (no pun intended).

So I think with two phone calls it's pretty well established DDT is banned from use in Australia. I by the way I asked if I can buy anywhere and was told I couldn't and that a seller of DDT would suffer the same consequences.

So I think I have established DDT is a banned substance in Australia. Anyone want to call the health authorities in countries to see if they can freely purchase it?

1. I called my local council and spoke to the health department. After I asked a dumbstruck woman I wanted to spray DDT around the house and garden she referred me to the state health authority, as she believed DDT was not an allowable substance. She said it caused cancer and therefore could not be used. I informed her that it was the first time I had ever heard that cancer was a cancer agent.
2. I then called the State Health Department. They told me DDT was not allowed to be used in Australia, as it was not on the APVMA register of pesticide agents. Referred to www.apvma.gov.au. I was warned if anyone was caught using DDT they would prosecuted, fined and most probably spend time in the can (no pun intended).

So I think with two phone calls it's pretty well established DDT is banned from use in Australia. I by the way I asked if I can buy anywhere and was told I couldn't and that a seller of DDT would suffer the same consequences.

So I think I have established DDT is a banned substance in Australia. Anyone want to call the health authorities in countries to see if they can freely purchase it?

David Bell:

See my later comments;

Dictionary definition of "to ban" is as follows:

1.To prohibit, especially by official decree
2.To deprive
3.A prohibition imposed by law or official decree
Thesaurus entry for the word is:
Main Entry: trade ban
Part of Speech: noun
Definition: trade prohibition
Synonyms: exporting ban, export sanctions, trade embargo, trade injunction, trade restrictions, trade sanctions, trading ban, trading sanctions, trafficking ban

I think as Australia goes DDT falls under these cats. Right? So the antibiotic argument can't really apply.

Tim's earlier reference to the website flogging the stuff is a red-herring as far as I can determine. Try importing the stuff into Australia? It's banned!

I want to empathize that I do not have an axe to grind about its problems with use/ resistance etc. I am no scientist and will defer to Tim an others who are more knowledgeable than I am about this problem. However, the use of DDT is banned under any definition. What worries me about this whole issue is that people in Government health departments who are supposed to know a little more than the average person make totally stupid comments such as DDT causes cancer when I have never seen a link attesting to that "unfact". How the hell does mis-information get around like that!

Pessimist,

I'm not sure how much of the previous discussion here on DDT you've read.

Yes. DDT is banned for effectively all purposes in the US and most other developed countries. The principal reason for the ban is that DDT is toxic to some species of sea-life and amphibians (as well as a wide range of insects other than mosquitoes).

DDT is highly soluble in fats and tends to accumulate in the body. While DDT itself doesn't appear to be particularly dangerous to humans it's tendency to accumulate and its known effects on other species are worrying.

The fact that malaria hasn't made a comeback in areas were it used to be prevalent like the south of Italy and Texas shows that you CAN control malaria without use of DDT.

So if everyone agrees DDT is banned in developed countries what's the argument over?

some people on the Right are claiming that

a. DDT has been banned from use for disease control purposes in developing countries

b. that this has resulted in millions of deaths.

The reality is that

a. DDT is used for disease control in many developing countries and

b. total deaths from malaria are around one million per year - compare this with hyperbolic claims about "millions of African children dying every year" as a result of the alleged ban.

Bob: ~60 years as an insecticide, but ~132 years 'old'

Ian: "b. total deaths from malaria are around one million per year - " Where do you get this figure?

All: With respect to concern due to resistances and cross resistances, I'm wondering why no one here seems to be proposing agricultural use pesticide restrictions on say, pyrethrum.

cytochrome:

Pyrethrum isn't used extensively outdoors. "Pyrethrum and pyrethrin products are used mainly for indoor pest control."

http://extension.usu.edu/files/agpubs/jul021.htm

With respect to concern due to resistances and cross resistances, I'm wondering why no one here seems to be proposing agricultural use pesticide restrictions on say, pyrethrum.

Pyrethrum is derived from plant compounds and is not a POP, nor do its breakdown products cause harm (see DDE'). Pyrethroids are also unstable, which is the reason why most pyrethroids are now synthesized and mixed with other goop to make a more stable compound.

Plus, IIRC from long ago, since the chemical is derived from plants, it is easier to confer resistance to bugs - the reason why man-made bug killers are so effective is their compounds taking longer to confer resistance (don't remember why any more).

BTW, Brian Schmidt: do enjoy your posts, sir.

D

Thanks D - if only growing plants were as easy as researching agricultural pesticides on the web, I'd have it made.

Cytochrome,

Check out the Wikipedia articles on malaria and DDT.

http://en.wikipedia.org/wiki/Malaria

Malaria ... causes about 350-500 million infections and approximately 1.3 million deaths annually, mainly in the tropics. Sub-Saharan Africa accounts for 85% of these fatalities.

http://en.wikipedia.org/wiki/DDT

DDT was first synthesized in 1873 by Othmar Ziedler, but its insecticidal properties were not discovered until 1939

Ian: Thanks for the links. I was wondering about your source as most estimates I've seen have been higher, or use 1 million as a lower bound, ie 1-3 million. There's an earlier WHO estimate of 1.5-2.7 million here:
http://www.cdc.gov/ncidod/eid/vol4no3/nchinda.htm

re: pyrethrum, I was referring to outdoor widespread agricultural use of pyrethrum and synthetic pyrethroids playing a significant role in vector resistance to DDT.(due to both targeting sodium channels)
I find it odd that there aren't NGO's pressuring African farmers to reduce the use of these pesticides as well.

In tangential news, the American Food and Drug Administration has withdrawn approval for Baytril (i.e., ciprofloxacin, i.e. Cipro) as a growth supplement for poultry. Between 1995 when Baytril was first marketed and 2002, the incidence of Cipro resistance in human Campylobacter infections rose from 0 to 21%. The ban was proposed in 2000, Bayer has been fighting it this long. Although 70% of all antibiotics used in the US go into agricultural feed as routine supplements, a practice which has long been attacked by public health advocates, this is the first time the FDA has pulled the plug on one of them.

I imagine we can expect an onslaught of astroturf organizations telling us that "The Cipro Ban is Costing Millions of Lives".

Regarding the malaria death rate, the Junkscience death clock footnote (see Deltoid, Jan. 25 2005) puts the current death rate at 2.7 million per year, which number I was able to corroborate at the time from a few sites via Google search. This obviously constitutes some kind of peak since the low point thirty years ago. I haven't been able to find estimates of what the death rate was then, or in the intervening years, but I haven't really knocked myself out trying.