In the news recently: Operation Rat Drop, where tylenol-laden mice were dropped from planes over Guam. It’s not a bizarre headache remedy; the idea is to try to kill brown tree snakes (a non-native invasive species) when they eat the mice. Acetaminophen kills snakes. Who knew?
That reminded me of a similar–but much odder–project: Operation Cat Drop. It’s an oft-told story about DDT and unintended consequences. I was excited to see it had recently been covered in a journal!
In 1955, a malaria outbreak in Borneo was fought by spraying DDT and other pesticides. Several unintended consequences were observed after the sprays, but time and distance have muddled them quite a bit. The basic claim is that local cats died after the sprays, and this caused an explosion of rat populations, which lead to increased human disease. The RAF then (in the more exciting versions of the story) parachuted in 14,000 cats to remote Borneo.
Some things are known and documented; one unintended consequence that did occur post-spray was that caterpillars eating the roof thatch of homes increased 50%, with associated roof damage:
”The WHO team sent to investigate determined that moth larvae (caterpillars) living in the thatch were able to distinguish the presence of DDT and so avoided eating thatch sprayed with the chemical, whereas their parasites, small chalcid wasps that injected their larvae into the caterpillars, were highly susceptible to DDT, causing their decline and the subsequent increase in caterpillar.”
This is a fairly classic pattern, where pesticides disproportiately affect natural enemies, or living organisms that act as natural brakes on pest insect populations.
It is also known that cats did often die after DDT sprays, and this was observed in several different countries on different occasions, including in Borneo. It would make sense that cats would eat rats and insects (and, in some versions, geckos) affected by the sprays, and the pesticide would biomagnify in their kitty bodies. That, however, does not appear to be the case; cats’ habit of grooming themselves and ingesting residue of the pesticide was what allowed them to receive a lethal dose.
Which leaves us with the parachuting cats. There was a rat problem in the area, and there is a record of 20 cats being dropped in Borneo by the British RAF, along with some chickens, by parachute. But that’s it. They weren’t in little harnesses; they were in special containers that would cushion the drop.
It’s a fascinating story of how something basic took on a life of it’s own. The paper I’ve cited below suggests that some of the story’s inflation in kitty numbers can be attributed to an expatriate Brit with a big ego that initially started the rumors. I don’t have access to his original document, which included little drawings of cats in individual parachutes, so I have done my best to recreate them here.
From there, the story was reproduced and took on a life of it’s own–I’ve seen versions where all the cats landed in the sea and drowned, versions where there were 10,000 cats, and versions where high-velocity falling cats killed people when they fell on them. All false, but far more interesting than reality.
Before anyone begins to trot out the usual “DDT will save us all” crap, I want you to read that paper and notice that it clearly lays out a whole sequence of unintended consequences from DDT sprays, including the problem of resistance from as early as in the 1950s. This paper is a reminder that we should not be uniformly pro- or anti-DDT; we should make pesticide decisions based on the best available, real evidence. Not propaganda.
O’Shaughnessy, P. (2008). PARACHUTING CATS AND CRUSHED EGGS The Controversy Over the Use of DDT to Control Malaria American Journal of Public Health, 98 (11), 1940-1948 DOI: 10.2105/AJPH.2007.122523
I read a lot of strange stuff on the internet. I mean, I’ve covered Extraterrestrial Cows and Mail-order public lice. But I really don’t expect to run into silly conspiracy stuff in Forbes, of all places.
In an article entitled “The Black Death: Longing for the Good Old Days,” James Taylor ties together global warming denialism, DDT boosterism, Edgar Allen Poe, and the Black Death (i.e. Bubonic Plague) to make…a really big pile of something that steams.
He suggests that everything was hunky dory when the climate was hot, but when things got cold–OMGPLAGUE:
“What brought about the Black Death? A thousand years ago, Europe was experiencing a golden age. The fair climate of the Medieval Warm Period, with temperatures similar to or warmer than today’s climate, stimulated bountiful crop production, supported unprecedented population growth,….
Longer winters and cooler, shorter summers decimated crop production throughout Europe. The rains that fell were cold, persistent, and slow to dry up. Famine and plague, which had largely disappeared during the Medieval Warm Period, became the norm rather than the exception. And by 1350, the grim, cold climate brought about the dreaded Black Death.”
He goes on from this to imply that environmentalists want to curb global warming in order to kill us all by bringing back the Black Death. Oh, and malaria, but we’ll get to that part later.
I actually have spent a lot of time over the years researching Bubonic plague, and the 14th century European “Black Death” in particular. I have never read of climate being implicated as a cause for the European plagues. Never.
I would also like to point out that the Little Ice Age actually occurred several hundred years AFTER the period of the bubonic plague outbreaks in Europe. A recent review paper listed the start date around 1570. So, the dots he’s trying to connect, in addition to being unrelated factually, are also unrelated chronologically.
The more interesting theories about why the Black Death was so devastating to Medieval Europe center on increasing urbanization and commerce. In order to have a massive epidemic, you need populations of potential victims to be concentrated. If you get the plague in the middle of nowhere, you will die horribly…and that’s it. There is no one to transmit the plague TO.
On the other hand, if you have concentrations of people in cities and towns; and you have movement of both people and animals between cities and towns, then you have a situation that is ripe for an outbreak. If you add in poor sanitation, it’s a dream for a disease bacterium.
There is a well-documented timeline of outbreaks moving from Asia over to Italy, and then up through Europe. Rats in grain and rats in ships moving from place to place for commerce were probably the primary movers of the disease. (In case you’ve forgotten, fleas are the vector of plague between humans and other animals. In other words, fleas transmit the plague bacteria from infected people/rats to new victims.)
Mr. Taylor is a lawyer working for the Heartland Institute, which advocates for unregulated trade (and also says that cigarettes are harmless). Somehow he seems to have missed the obvious connection between free markets and plague. Hmm.
So, what else? Oh, the Malaria–right. From the article:
“Malaria was becoming a distant memory 50 years ago, but the World Health Organization now reports that over 200 million people contract the disease each year and nearly one million people die from the disease each year. A single, small application of DDT to the inside walls of a hut – in which malarial mosquitoes most frequently infect their victims – will keep malarial mosquitoes at bay for months, but environmental activists have forbidden this chemical infringement on The Natural Condition.”
Let’s start with that first sentence. 50 years ago, Malaria was becoming a memory for the US and Europe; they launched very successful campaigns to control mosquitoes. Malaria eradication was not, however, successful in Africa, Asia, or Latin America. In fact, some areas never were part of any Malarial control campaign. It’s certainly correct to say that too many people die of malaria each year; but it is not correct to say that more die now than in the past. If you look at WHO data for most regions, there is a clear downward trend. Global control of malaria has been slowed by resistance to treatment drugs, as well as mosquito resistance to DDT.
Which brings us to his next claim. In his second sentence, he claims that DDT can be applied to the walls of a “hut” and provide protection from malarial mosquitoes. News flash–not everyone lives in huts–your imperialism is showing. But, hey, let’s run with it.
This is an incorrect statement for a variety of reasons. Indoor Residential Spraying (IRS) is actually not a preferred methodology for the World Health Organization Malaria group; they specifically recommend against using the same chemical year after year. Increased resistance to pesticides is strongly tied to indoor sprays in the report I linked. A quote: ”it is unlikely that universal vector control coverage can be achieved in Africa by IRS alone.”
Taylor’s pollyanna approach ignores the the reality of DDT and malaria in the world today. A hundred countries currently have a malaria problem. It is patently absurd to think that one single chemical (and methodology) can solve a problem that is global in scope.
There isn’t only ONE species of malaria mosquito–there are dozens (And they don’t all bite you when you are inside). There is not just ONE kind of ecosystem in which people and malaria interact. Designing a malaria control methodology has to take into account the political, environmental, and socio-economic situation of a particular community. What, if any, data do we have on the resistance of the mosquitoes to insecticides? It is not a one-size-fits-all problem with one solution.
His last sentence is also untrue. DDT is part of current WHO treatment guidelines. It is not “forbidden”. But DDT is only one piece of a huge, huge complicated problem, and over-reliance on it can actually make things worse by leading to greater insecticide resistance.
What I want to know now is–Why did Forbes let this douche write an article full of BS that was VERIFIABLY FALSE? And what are they going to do about it?
I was interviewed by Drunken Skeptics (Michigan Skeptics Association) about DDT, bed bugs, and my criticism of Brian Dunning for not doing proper research and posting a lot of incorrect stuff about DDT.
I’m actually rather pleased with how it turned out, although you can clearly tell I had a cold. I’m interested in feedback from some of my fellow bloggy entomologists about whether you think I represented the larger entomological community’s views on DDT correctly.
The biggest complaint I have about the whole manufactured controversy surrounding DDT is that it’s a waste of time and energy, and distracts from the real work we need to be doing. DDT boosters like to frame the argument as: “Which is worse, Malaria or DDT?”
They have framed that question so that there is only one possible choice. A forced choice between Malaria and DDT is the WRONG QUESTION. I completely reject that false dichotomy as oversimplification. There are more than two choices.
The real discussion that needs to happen is about the best way to control malaria and improve human health in a particular situation. Over 99 countries have a malaria problem. It is patently absurd to think that one chemical can solve a problem that is global in scope. DDT is part of current WHO treatment guidelines. But it is only one piece of a huge, huge complicated problem.
What is the political, environmental, and socio-economic situation of a particular community struggling with malaria control? What, if any, data do we have on the resistance of the parasite and mosquito vectors to drugs and insecticides? It is not a one-size-fits-all problem with one solution.
Because of the vitriol that is spewed, people like me (and probably a few politicians) are hesitant to talk about Malaria at all. It makes aid to the WHO and Africa a political football that is used to score points. It’s not, really, about DDT at all. It’s about tarring and feathering the environmental movement, and keeping people distrustful of science.
And that is sad.
I’d really like to type up a transcript for the podcast, but I still am under the weather health wise–hopefully I can do that next week.
A few weeks ago, Brian Dunning of Skeptoid posted a podcast that made a variety of claims about DDT and Rachel Carson’s book Silent Spring that were poorly researched and factually incorrect. For a while Dunning refused to admit his error; the podcast page as of 11/23/10 now has a box at the bottom in which he distances himself from the DDT claims he made by saying “Skeptoid is not here to tell you what to think.”
I and a few other people have been writing for several years about the way in which right-wing groups have been promoting DDT and attacking Rachel Carson. I could easily do a point-by-point fisking of Dunning’s mistakes (which others have done ably; see links at the bottom of this post), but I think the most useful thing to do would be to examine why a prominent skeptic fell so hard for a bogus manufactroversy.
“Manufactroversy (măn’yə-făk’-trə-vûr’sē). A manufactured controversy that is motivated by profit or extreme ideology to intentionally create public confusion about an issue that is not in dispute.”
You see manufactroversies all the time in the media– “Teach the Controversy!” “Global Warming is a hoax!” “Vaccines are poison!” The common thread is creating a controversy even though a clear consensus exists within the scientific community.
Media likes to frame issues as a debate: if you can get two talking heads to argue, that’s great TV. The problem is, presenting both sides of an argument is silly when there is no actual lack of consensus.
Dissent is manufactured by using information out of context and/or finding a scientist that opposes the prevailing view. That lone scientist’s opinions are then given equal weight to the majority of scientists who don’t think using DDT indiscriminately is a good idea. Or that Global Climate Change is a real and major threat to ecosystems. You get the idea.
Manufactroversies also exploit the way in which scientists are constrained to speak in probabilities, not absolutes. It’s part of the language of science to say that something may be true, almost surely IS true, but there are caveats on the conditions under which something is true. Scientists also have to make statements open to revision based on new information.
That’s part of what Skepticism is all about, too–forming opinions based on the available evidence. New Evidence? Re-assess your conclusions. This is not, alas, how many major media outlets–or politicians–operate.
The primary source Dunning seems to have used for his DDT fiasco is a website called Junkscience.com. Junkscience has an amazing history, and a little follow the money helps to connect cigarettes, lobbyists, anti-environmentalism, and an astroturf group called Africa Fighting Malaria. Why didn’t Dunning pick up on those red flags? I don’t know.
The reality of DDT and malaria is that it is an incredibly complex problem. There isn’t only ONE species of malarial parasite (Plasmodium). There isn’t only ONE species of malaria mosquito. There is not just ONE kind of ecosystem in which birds, mammals (including people) and malaria interact. There is not just ONE political and health care system in areas where malaria occurs that is optimal for managing treatment. In fact, in some areas where malaria occurs, there is no effective political or health care system!
Each system is different, and that is why blanket statements that portray DDT as a panacea for solving malaria problems are false and, frankly, stupid. The issue of insecticide resistance is not trivial. We have many tools in our insect control toolbox; we need to choose each chemical carefully based on the best chance of control within a particular context. Making the wrong choice can have serious consequences if resistance occurs, and we loose the use of a pesticide.
When people espousing careful examination of data before making an insecticide choice are attacked for promoting “genocide”, you have to know something else is going on. There is a political agenda at work.
I can guarantee you that within 24 hours of this post, there will be at least one, probably more, commenters that will accuse me of racism (“you want to kill brown people in Africa!”) or of lying about DDT. They have shown up all over my blog whenever I bring up the topic of DDT and Rachel Carson. Their primary methodology is copy/paste of the same old tired arguments over and over.
These are not people interested in nuance or conditionality of conclusions. They are people that find information that fits with their already existing world view, and then adopt it. Because it supports what they already believe.
Carson’s principal thesis was that broadly biocidal chemicals should not be carelessly introduced into the ecosystem. She also said this: “It is not my contention that chemical insecticides must never be used.” I don’t think many here would disagree with those statements.
Had Dunning actually READ Silent Spring, he might have realized his own words were wildly incorrect: “Silent Spring’s principal thesis was that DDT harms bird populations through eggshell thinning.” In fact, the evidence for eggshell thinning was not published until after Carson’s death from breast cancer in 1964. (Also, when writing a critique of a book, it helps if you actually read the fucking book. But I digress.)
Dunning clearly got his information second-hand. And it was bad information. This should be a lesson to all of us to check our sources carefully, and ask questions about “Who Profits?” and “What’s the Motivation?” about everything we read. And to be willing to own it when we screw up.
- Dunning DDT Fact Check (part 1)
- Dunning DDT Fact Check (part 2)
- Did Rachel Carson kill people by DDT whistle blowing?
- Mosquito resistance to DDT and other insecticides
- DDT primed bedbug populations to be resistant to insecticides (video)
- Bedbug insecticide resistance
- How well have claims in Carson’s 1962 book held up? Pretty well, actually!
- Who put the hit on Rachel Carson?
- Follow the money
- Bate and Switch: how a free market magician manipulated two decades of environmental science
- Rehabilitating Rachel Carson
- Africa Fighting Malaria 2007 Tax return (PDF)–all their money seems to go to salaries, rather than actual…..malaria fighting. Huh.
I discovered that bed bug evolution–specifically resistance to pesticides–was also the subject of the National Evolutionary Synthesis Center‘s podcast this month. A FASCINATING interview with one of the grand old men of evolutionary genetics, James Crow. He worked on DDT resistance back in the late 40s and 50s.
“Like pyrethrums, DDT kills insects by acting on the sodium pores in their nerve cells — and it just so happens that many of the same mutations that protect an insect against DDT also happen to protect it from pyrethrums. When DDT was first introduced, such mutations were probably extremely rare. However, with the widespread use of DDT in the 1950s and 60s, such mutations became much more common among bed bugs through the process of natural selection. Though DDT is rarely used today because of its environmental effects, these mutations have stuck around and are still present in modern bed bug populations. Because of the action of natural selection in the past (favoring resistance to DDT), many bed bug populations today are primed with the right sort of genetic variation to evolve resistance to pyrethrums rapidly.”