Has Rachel Carson or DDT killed more people?

I remember recently reading on the Internet that DDT wasn’t really as bad for the environment as thought and that the research cited in Silent Spring was subsequently found to be flawed. The article (Fox News - I think) also said that the World Health Org. had managed to get DDT outlawed in third world countries and people are being killed by insect borne disease in record numbers. So what’s the Straight Dope?

Not trying to say that these links will answer all of our questions corrctly, but they may help.


and our own previous discussion http://boards.straightdope.com/sdmb/showthread.php?threadid=10733

I remember seeing footage of DDT being sprayed directly onto kids at a swimming pool, sitting at a picnic table eating. That seems kind of icky.

Personally, I’d rather eat my veggies fresh without chemicals like DDT.

Rachel Carson is a local hero here in Pittsburgh. Were it not for her, we might still be known as Hell with the Lid Off, we’d still be using streetlamps at noon. (I believe she protested that too, but I’m not sure).

Well, since there is not a single recorded death attributable to DDT, I’d have to say that Rachel Carson wins hands-down.

Oh, I can beat that. You know what’s ickier? Seeing hundreds of children’s bodies stacked like cordwood in an open grave after an outbreak of malaria.

DDT prevented that. Malaria used to kill tens of millions of people a year. When DDT spraying programs started after WWII, for example, there were 75 MILLION cases of malaria each year in India alone, and about 800,000 deaths. Within 10 years, Malaria was almost nonexistant. The number of cases overall dropped from 75 million to 50,000, and the number of deaths from 800,000 to zero.

By 1962, Malaria was on its way to being completely eradicated. But then ‘Silent Spring’ was published, and pressure by rich white folks (who never had much of a malaria problem to begin with) caused an eventual bban on DDT. Almost immediately, malaria deaths started to rise, and today about 1.5 to 2.7 million people a YEAR die from malaria.

My personal opinion is that this is a racist policy. I know environmentalists tend to become apoplectic when I accuse them of being racists, but the facts stand for themselves. Does anyone believe that DDT would have been banned if 800,000 people a year, most of them children, were dying from malaria in the U.S. every year? Not a chance.

But those little dead kids are typically poor brown kids in little-known places in Africa or South America, so we magnanimously decided to prevent eggshell thinning in raptors by banning the one thing that gave a little ray of hope to an otherwise miserable existance for those people.

So to whatever extent ‘Silent Spring’ helped bring about the eradication of worldwide DDT disease vector control programs, Rachel Carson is indirectly responsible for the deaths of millions.

BTW, I do understand the other issues surrounding DDT, and there is no question that it was being over-sprayed, especially in agricultural spraying programs. But DDT is not even available to many people who wish to spray it inside their little shacks, which would at least give them a fighting chance. And there is ZERO evidence that DDT used indoors harms either humans or the environment.

And the current alternatives to DDT are 3-4 times more expensive, which also makes them unavailable to the people who need it most.

Oh really? Then you go ahead and spray it in your own house. Just keep your windows closed please. :rolleyes:

Sam Stone said

Sam, any chance you dropped a decimal point here??? :eek:

JunkScience is steeped in exactly what it claims to be all about exposing - twisting science deceitfully to advance a political agenda. Don’t lose sight of the point that JunkScience is reached from the Editorial page! And just what the Hell is a “biostatistican” anyway? Does that make you an expert on physics, chemistry, toxicology, ecology, and economics? Hey, I’m a speleostatistican, maybe I should start a column on national defense policy.

The problem with DDT isn't necessarily it's toxicity to humans, but to many other animals. It breaks down very slowly, and accumulates as it moves up the food chain.

Reading the referenced SDMB thread, I see repeated reference to the "Western Greens" saying the environment is move valuable than "poor brown people". The problem with this argument is that without a healthy, functioning environment, there won't be any poor brown people, or poor white people, or rich people or any people at all.

And a healthy environment requires diversity. The anti-environment band always present these issues in this fashion - to stop a dam to save snail darters, or to halt logging to save owls is to value them over jobs and families. But to weigh any single species against human interests is folly - the single species will always lose out, and one by one (more often hundreds by hundreds as more and more habitat is lost) enough will disappear to cause a huge collapse of the general ecosystem. Will life disappear? Nah, the biosphere has survived a lot bigger disasters than what we're doing, take for example the matter of that little comet in the Yucatan 65 million years ago. But from every mass extinction, and lots of little ones like North America 10,000 years ago, there's one obvious fact - large animals, say greater than 50 kg, take it on the chin. That's us folks, and for all kinds of reasons, too, though the biggest are probably related to be the fact that there's just so many fewer of us and we breed so slowly. (There's probably more ants in Kentucky than people in the world, and there's definitely more nematodes in Harrison County. Hell, I think there's more ticks on my farm, for that matter. <grin>)

No single strand of a net is critical either, but break enough and the entire thing will fail, and catastrophically, too.

It makes more sense to save entire ecosystems than individual species, but unfortunately that takes land - and lots of it. ANWR for one - but hey, the same people who claim the ESA has the wrong focus (one species at a time) are the same ones who want to open up the ANWR to industrial exploitation. There are plenty of people, with money, power, and influence, who will oppose any environmental protection effort if it will keep anyone from making a single buck. And one of them writes JunkScience.

Samclem: No, I didn’t drop a decimal point. Malaria has probably killed more people than any other disease known to man, including the plague. TODAY, almost 3 million people a year die from Malaria, and that’s with some (mostly illegal) use of DDT, use of DDT replacements in countries that can afford them, and a much better understanding of disease vectors that has helped us drain malarial swamps that breed mosquitos, etc. Before modern science, malaria affected the population in about 40% of the world. Today, it’s down to about 10%. And with modern medicine, more victims survive than they used to. So ‘tens of millions a year’ is an accurate statement. Or were you suggesting that it was hundreds of millions a year?

Speleophile: Okay, so tall me just how indoor residential spraying of DDT destroys the environment. I’ll be the first to admit that it was overused - the wildly successful results it first had caused it to be sprayed on damned near anything. But indoor residential spraying puts only the tiniest fraction of DDT into the environment that agricultural spraying does.

DDT is a perfect example of what’s wrong with the “Precautionary Principle”, which basically says, “When in doubt, ban first and research later.” The costs of a ban can be tremendous, both economically and in human life. DDT should never have been banned. Agricultural spraying, fine. But an outright ban of a substance which has demonstrably saved hundreds of millions of lives without adequate research into alternatives or other application techniques is criminal.

Sam I respect you as a poster. I just wonder if you can give me a cite that says 20 million people or more per year died of malaria prior to the discovery/use of DDT.

Speliophlile I appreciate you challenging the JunkScience source. I never took a look.

skeptic seems to think that the site is rather biased but says

I’m trying to balance the Anti-DDT article with the “conservative, Rush Limbaugh” comment. Currently confused, but will read more tomorrow.

If I lived in a malarial area I’d do it in a heartbeat. You’d be a damned fool not to. Would you rather expose your kids to a chemical that really doesn’t have any proven effect on their health at all and is substantially less of a burden on the environment that the computer you’re using right now (the power’s coming from somewhere, you know) or expose yourself and your family to a horrible, vile disease that can kill you? I’ll take the DDT, thanks.

Whatever else is true, the fact is that DDT virtually eradicated malaria and banning DDT brought it back in force. If DDT spraying was still used throughout the world a great many children would be spared a horrible death.

Sadly, malaria is not a fashionable disease; nor is diarrhea, the other major killer of children in the third world. We get benefit concerts and celebrity endorsements for every disease except the two that, combined, will kill at least four million people this year.

There are also plenty of other people who simply want to be a thorn in the side of business, knowing that they’re not the ones who are going to suffer. Nitwit thinking about the environment is found on both sides, probably in equal proportion.

As for DDT, it seems to me a case of overreaction. Were the lives saved the children of those who banned the substance, you can be damn sure that alternatives to a complete ban would have been strongly considered. To claim that any DDT use is intolerable is simply constructing an all-or-nothing false dichotomy. DDT is not incompatible with a healthy environment. However, as long as the tens of millions of lives at stake are far enough away, we can give this one to the environment, and feel that we’re doing right by mother earth as we sit in freeway traffic in our SUVs.

Hmm… I suppose that we’re getting into GD territory here.

Sam Stone: Well, I can be convinced by reasoned debate. If sprinkling a little around the house would eliminate mosquitos and malaria, it might be worth the trade off of some of it leaking into the general environment. However, to be effective, I though DDT needed to be sprayed exactly where it will do the worst environmental damage - in the wetlands where they breed. I don’t see how spreading it around the house is going to help - how do they come in contact with it? If I’m wrong, and small, localized applications to human housing will significantly reduce their numbers and prevent malaria, please provide a reference.

Waterj2: Yes, there are people out there who like to throw wrenches, if only to see sparks, not denying that. Nitwit thinking is found on both sides of the issue, but I sort of doubt it’s equally evident, for one simple reason. There’s lots of money to be made on one side, and the less you have to worry about environmental issues, the more you make, but on the other side there’s just not much monetary incentive.

A total ban on DDT may, or may not be over-reacting. I don’t have enough facts at my disposal to judge. (See preceeding note to Sam)

And the U.S. is certainly not completely on the side of the angels here, either, your point on the SUVs well taken. But it’s irrelevent to the DDT issue unless you’re taking the attitude that, screw it, if we can’t get everything perfect, why bother fixing anything?

As for malaria deaths:

from drkoop:

from the Seattle Biomedical Research Institute

The only figures for historical levels I can find on hand are from this site, and show that in India alone, between 1947 and 1961, total malaria cases were reduced from 75 million (with 8 million deaths) to 50,000. In 1976, the number was up to 6 million, and now is around 2 million (with 648 deaths).

Malaria.org mentions that due to DDT spraying “in only 8 years, Sri Lanka went from a million cases of malaria a year to only seventeen” and after DDT use was stopped “within a decade, malaria rebounded to nearly a million cases a year.”

You’ve all completely missed the point, something that thankfully rarely happens on the SDMB.

DDT is not especially harmful to humans. It was banned in 1972 because it was conclusively linked to thin eggshells in bald eagles, ospreys, and other birds, so that the egg cannot bear the weight of the mother when she tries to incubate it. It is a chlorinated hydrocarbon (as are PCBs) which accumulates through feeding in animals at the top of the food chain. After the DDT ban, the populations of the affected species rebounded dramatically.

The tradeoff is therefore simple: If you allow widespread use of DDT, certain highly appreciated birds will become extinct. That has to be balanced against any positive effects DDT has against malaria, etc. I don’t have an answer to the dilemma, I’m just stating it clearly, which is certainly a prerequisite to any intelligent discussion. I suspect there are substitutes for DDT that don’t ruin the bird population, and they never would have been developed had DDT not been banned.

An anecdote: When I worked in Japan, shortly before DDT was banned there, the janitor in our building would walk down the aisles once a week, spraying DDT on every exposed surface. I also noticed that there are very few wild birds in Japan; in fact, the lobbies of many buildings play recorded bird chirps in the morning.

Eh, not quite. A good deal of data from England, Denmark and the US show that DDT and DDE both are implicated in human endocrine toxicity. Granted, not an immediate squirming death, but pretty dang bad nonetheless. The eggshell thinning was just the more obvious pathology evident in wildlife with its smaller generational times, that tipped off its effects on reproductive biology.

Having unfortunately had malaria [three strains] several times, I’d point out that the deaths are typically from inability to provide water, antifebrile medications, etc… so while I do not mean to lessen the sorrow of numerous deaths from the disease, the idea that DDT “stops” it is not a black-and-white as you make it out. The disease is more typically fatal from the inability to fight off or mitigate its symptoms. (Not to mention the issue of eventual DDT resistance in the bugs…)

While DDT residues do not provide complete protection from malaria transmission, they do provide variable but significant levels of protection for months after walls are sprayed

A field trial was undertaken to study the impact of mud plastering on the efficacy of DDT spraying in two villages in Koraput district. In Maliguda village, where 95 per cent spray coverage was achieved and the spray surfaces were retained without mud plastering up to 29 and 60 days in first and second round of the spray respectively, malaria cases reduced by 72 per cent after spray for a period of two months. In Dandabedha village with 85 per cent coverage and immediate mud plastering, the malaria cases reduced by 49 per cent. It is concluded that even though mud plastering reduces the effectiveness of the residual spraying to a certain extent, timely spray and better coverage with correct dosage can still effectively reduce the malaria incidence.

The reason why localised applications work is as follows.

After feeding a mosquito will land on the nearest surface to concentrate the meal by removing the water. At its most infectious stages malaria incapacitates it’s victims, who will almost always be inside in bed. Even if this is not the case most bites occur at night. If all walls are sprayed with a surface agent such as DDT a full or partially fed mosquito will land on the walls, picking up the agent and becoming incapacitated within minutes. In this way no transmission is possibe from hosts that are inside when bitten. Since many (most?) areas have no natural reservoir for malaria such an approach is highly effective at malaria control.

For more detailed information refer to any good pest control text. I’d recommend the chapter on mosquitoes and flies in “Urban Pest Control in Australia. Hadlington, P. and Gerozsis, J. 2000, UNSW Press”, but I don’t imagaine most people can get ahold of it. There should be similar tects available in other parts of the world however.

The question is an obvious troll, since the terms of it vastly oversimpify the situation.

DDT was instrumental in reducing deaths due to malaria. But it wasn’t spraying for malaria that Carson was warning about. DDT was in widespread use when she wrote “Silent Spring,” and most of that use and abuse was on the part of people in the developed world. There was a recent New Yorker article that indicated that the amount of DDT used on a single good-sized farm was more than was used in spraying for malaria all over the world in a year. The malaria fighters had learned how to be careful – to spray only where the mosquitoes gathered. But others had not. In a perfect world, there would have been just a ban on the agricultural uses (and I believe that was the situation in the beginning). But since this isn’t a perfect world, the only way to stop the overuse was to ban it completely.

DDT was by this time beginning to lose its effectiveness, anyway. DDT-resistant mosquitoes were becoming more and more common. So ultimately, the malaria fighters would have moved away from DDT in any case.

So this is a straw man. Carson didn’t kill anyone, and her book had only a slight effect on the anti-malaria campaign.

EPA says that DDT is a potential human carcinogen and
endrocrine disrupter.


So, I don’t think we should write-off the human health effects of DDT (in addition to the ecological risks to birds, etc.) but certainly the malaria problem in other countries deserves more attention. Widespread application of DDT is wrong (dangerous) but perhaps limited application has its place.

Ideally, it would be good to find a safer alternative that was also effective at eliminating that disease vector.

Not sure how serious you are here, spelophile. A biostatistician is a statistician that specializes in biological data and analysis. I’ve worked with them for the last 5+ years, it is a absolute legitimate branch of science.

I didn’t read any of the links, so I don’t know exactly what you’re being sarcastic about – obviously, it doesn’t make you an authoratative expert on any of those things, but it gives you a basic knowledge of many of them, and hopefully any statistician worth their salt would have useful expertise to lend to a question like this. In other words, I wouldn’t accept anything just because a biostatistician wrote it, but I wouldn’t automatically discard it either.