Slashdot Mirror
DDT or Malaria -- Which is Worse?
Assassin bug wonders: "Although the topic of malaria has been discussed on Slashdot, DDT use has not. After having banned DDT (C14H9Cl5)" in 2004, Tanzania has reversed their ban on DDT use. What is the Slashdot community's opinion regarding the use of DDT for mosquito control versus genetically modified mosquitoes?"
"Key facts to consider:
- Insects have developed resistance, for every tactic that has been used against them (including biological control, crop rotation, and various chemicals)
- Although the direct effects of DDT on humans might be benign, the effects on wildlife and the environment are well documented
- In some countries, such as India, popluations of DDT-resistant mosquitoes exist
- The fitness (i.e., reproductive success in the wild) of mutant mosquitoes is not well understood."
The alleged environmental impact was when the use was ultra-widespread, like dusting crops.
DDT is effective at fighting malaria in much of the world, applying just around the home, but chemical manufacturing companies largely stopped making it after it got a bad name from the environmental concerns.
-- Erich
Slashdot reader since 1997
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The answer is frogs. Big freaking frogs. With lasers on their heads!
The DDT necessary to save thousands of lives in the world's malarial hellholes is miniscule compared to that required for the crops of even a medium farm.
And DDT-hate on the part of international aid organizations (international aid is the entire health budget for some impoverished African countries) has led to countries refraining from using DDT.
Not using DDT kills poor Africans.
DDT is the cheapest, most effective way of protecting against the world's deadliest disease. Anti-malarial netting is somewhat effective, but simply does not compare to DDT.
"It is more sensible in some cases to take a small amount of damage in preference to having none for a time but paying for it in the long run by losing the very means of fighting [is the advice given in Holland by Dr Briejer in his capacity as director of the Plant Protection Service]. Practical advice should be "Spray as little as you possibly can" rather than "Spray to the limit of your capacity.""
-Rachel Carson, Silent Spring
Note the last sentence. It seems she KNEW that in some cases, not using DDT would amount in a LARGE amount of damage, and in these cases, using DDT would be unavoidable. Spray as little as you possible can seems to be common sense, but may not be to the uneducated.
It IS known that DDT builds up in the tissues of organisms high up in food chains. Perhaps studies don't indicate that DDT directly causes any sort of harm, but I don't think having an organochlorine in ANY fleshy parts is a good thing.
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The problem with pesticides and antibiotics is that they are often abused and misapplied through ignorance, stupidity and greed. Read how China may have fscked the entire world by using a human antiviral drug in an effort to protect the Chinese poultry industry from bird flu.
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Mosquitos that are resistant to malaria, meaning that they are no longer carriers of malaria and can no longer spread it to humans, but the Slashdot article was very muddy on that!
Here's an interesting DDT FAQ entitled 100 things you should know about DDT.
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Dr. Lambert has made a hobby of following DDT opponents' crazy theories, as well as the anti-global-warming crowd, and the Big Money that makes both possible. For a compact overview of DDT falsehoods, check out DDT ban myth bingo.
Your quote says this:
"DeWitt reported no significant difference in egg hatching between birds fed DDT and birds not fed DDT"
and then, one sentance later, this:
"DeWitt's report that DDT-fed pheasants hatched about 50 percent more eggs than 'control' pheasants."
Now, I don't know who DeWitt is, and I don't claim to be knowledgable about DDT, but these sound like contradictory statements to me!
Maybe spiked-online and/or DeWitt have a vested interest in DDT...
> DDT or Malaria -- Which is Worse?
I don't think it's a 1:1 comparison. Killing mosquitoes is analagous to killing terrorists...you don't stop them from breeding. A proper mosquito-control regimen involves maintaining healthy (warm summer) climate so dragonflies are healthy and eat the mosquito larvae the moment they pop out of the pond.
You should see a pond with dragonflies hovering...it looks like the Congratulations screen from a videogame. Each dragonfly takes a 10' radius, so a group of them has the whole pond on lockdown.
Found your comment interesting, so I googled it and found this very interesting. Thought others might find it a good summary.
Click on the top link about borneo on this Harvard Page
As for his DDT stuff -- it's complete rubbish. In the 60s the World Health Organization tried to eradicate malaria by spraying DDT and failed. There are several reasons why it failed, but one of them was the indiscriminate use of DDT in agriculture, which was a very effective of evolving DDT-resistant mosquitoes. DDT is still useful in the areas where the mosquitoes are not resistant and for that you can thank the ban on the agricultural use of DDT. In other words that ban, far from causing 50 million deaths, has saved lives. You can read about the failure of the malaria eradication campaign here.
Then there is Methoprene - a compound that is similar to an insect growth hormone. It targets specifically insect larvae and prevents them from reaching their next stage of development. Again, it can be used like any conventional insecticide, does not accumulate and is easily biodegradable and non-toxic to anything but insects. Has been successful in trials against mosquitoes as well.
So, why DDT?
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Where considering I am currently living in Tanzania helping installing Linux servers for rural ISPs, after only 3 months I have seen 14 people die from Malaria. For these people, they live day to day and do not think of the future. So for them, using DDT as a right now treatment vs possible cancer many years from now, there is no debate.
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For reasons best known to themselves, some parts of the blogosphere have taken up the meme "By banning DDT, environmentalists have caused the deaths of millions of people from malaria." Almost every aspect of this meme is false, as anyone can discover with a small amount of Googling. I can even save you the small amount of Googling by pointing you to Deltoid, the blog of someone who has done it for you. The "Rachel Carson was worse than Stalin" notion seems to have been started as an astroturf lobbying operation by DDT manfacturers, and spread by dittoheads. Some wingnut sites have counters suggesting that the death-toll is even billions, which just goes to show how innumerate some people are.
The "DDT is dangerous" has been conclusively and comprehensively DEBUNKED years and years ago. There is NO reason this crap needs to continue, except for the psychological agenda of the enviro-facist movement.
http://www.junkscience.com/ddtfaq.htm
Basically, 'Silent Spring' was based on test data that was wrong.
The birds whose eggs were shattering, had been raised on a diet containing less than 20% of the calcium they usually got. Duh. Low calcium = weak eggshells.
When the experiment was repeated with a proper diet, there was NO such finding, even in birds HEAVILY fed DDT.
Even the original authors of the experiment had, by 1971, turned their investigations more to PCBs, and discounted DDT as an issue with bird populations.
An administrative Judge ruled even at the time that DDT wasn't dangerous.
Nevertheless, the administrator of the then-new EPA ruled it would be universally banned...and then promptly went to work for the exact same anti-DDT enironmental lobbying group, after he left he EPA.
But I find that DNR staff, ecological speakers visiting schools, reporters, etc all have cheerfully and unquestioningly swallowed the Kool Aide on this because of its SEMINAL impact and justification of the environmental movement. To be fair, when confronted constructively about it, are rather shocked but eventually persuaded that there MIGHT be some doubt...which is a lot when you're attacking such a sacred cow. However, I have yet to see anyone subsequently change their presentation, curricula, or (effectively) beliefs.
Question that DDT might not be dangerous? That might make people wonder about the validity of the whole "movement", if they could be shown to be such easily-gulled rubes.
Heck, it might even make you think global warming is BS...but no, that MUST be true, right? Scientists say it is.
-Styopa
Read: http://www.reason.com/rb/rb010704.shtml for a simplified history on the subject.
This is the first thing I've heard contrary to the "fact" that DDT causes thin shells.
It's not a question of ALL birds it about a small number of sensitive species.
"Anderson notes that DDT and DDE levels in nature have been falling for decades. Populations of bald eagles, peregrine falcons, ospreys, and brown pelicans have all bounced back. In 1969, researchers reported finding total DDT accumulations ranging from 5,000 ppm to 2,600 ppm in the fat of North American peregrine falcons. Today, one would typically find 50 ppm in raptors, according to Anderson. Such body burdens would yield only about 2.5 ppm in eggs. Anderson notes that there appears to be a threshold of one to three ppm for DDE in eggs below which there is no eggshell thinning in even sensitive bird species. Dusting DDT on the walls of houses in developing countries to control for mosquitoes seems unlikely to cross that threshold for birds.
Banning DDT saved thousands of raptors over the past 30 years, but outright bans and misguided fears about the pesticide cost the lives of millions of people who died of insect-borne diseases like malaria. The 500 million people who come down with malaria every year might well wonder what authoritarian made that decision."
Thousands of raptors should read 100's of thousands perhaps millions vs "Malaria afflicts between 300 million and 500 million people every year" (http://en.wikipedia.org/wiki/DDT) but I still agree with his conclusion. We should limit DDT's use and avoid wide spread spraying but it's fine in limited areas.
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This is known in reasoning circles as a "false dilemma".
DDT is very cheap and effective in the spot you're applying it to. And therein lies the problem: it's almost too good. The step from using it where it is effective and safe to using where it has unwanted side effects has historically proven to be very short.
Lacking DDT, the industry has had to develop alternative approaches, such as IPM, which are more information and biology centric, and new materials which are more narrowly targetted and which break down in the environment in a more benign way. This requires more up front effort and investment, but in the end is probably more effective.
Consider one common traditional use of DDT: Fogging to kill adult mosquito populations. The mosquito has to encounter the DDT on the wing or land in a place where there was residual toxic effect. Since the mosquito could be literally anywhere, this means you must saturate an entire area surrounding human habitations by fogging it. In the old days, you waited for a nuisance problem or a disease outbreak, and then fogged everything you could reach and hoped you were in time to stop human transmission. I've talked to public health researchers who believe that most such efforts tend to be undertaken after the actual problem has past. Or if you were proctive, you might try to treat preventatively, killing not only mosquitoes (you never get them all), but beneficial insects as well.
Today, if you can manage it, you find the aquatic habitat in which mosquito larvae hatch and develop, and if you can't drain it (e.g. artificial containers like abandoned machinery), you treat it with a narrowly targeted larvicidal material. BTI and Baccillus sphaericus for example, are endotoxic crystals that only act in aquatic larvae with high pH guts -- midges and mosquitoes mainly. If the mosquitoes have pupated, you treat with a material which forms a film on the water, blocking their breathing tubes; in the old days we used diesel oil, now we have specially formulated oils and even alcohols that form monomolecular films.
However, this involves knowing where the habitat is, which is information-centric problem. You need trained inspectors in the field who know what to look for and what to use. Even fogging operations are much more sophisticated; you don't just spray and pray. You have a trapping program to monitor adult populations so you don't end up fogging the wrong places. The technology involved for trapping is mostly rudimentary , but you need trained users who can sort and identify mosquitoes by species. Not all mosquitoes bite people or carry disease after all. Furthermore you'd be surprised how many untrained people mistake other insects such as crane flies for mosquitoes.
But it remains thrue, for the developed world Information + Biological Knowledge + Specific action pesticides = Control with fewer side effects.
With respect to human and animal health, there is little threat to human health from direct exposure to DDT in the concenrations that are effective. The established problem with DDT is bioaccumulation: the concentrations of DDT and chemical products of DDT break down are amplified as they go up the food chain. In certain key applications, such as house interior treatments, this is not a concern however, so it should be possible to use DDT this way.
In places like Africa, DDT used in domestic treatments would be a tremendous boon. The forms of Malaria that infect humans, unlike many other mosquito borne diseases such as the various encephalitis agents, don't have a natural animal reservoir. It spreads from person to person. Personally, I can imagine Malaria being eradicated, like smallpox, and domestic DDT treatments could play a part in this, if its use could be monitored and controlled.
I've been involved with equipping teams to go to Africa for malaria surveillance and for house treatments. One of the problems you face is that in many poor areas, theft is rife. I've had guys tell me they have
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I still think that the best source of stories on the overuse of erratication programs is Laurie Garett's The Coming Plague. She discusses how the Small Pox eradication (one of the most successful) weaponized small pox, how cleaning with bleach has bread super-bacteria in some hospitals that can be cultured on undiluted Clorox.
Her point (about antibiotics and mosquito control) was that we should try to domesticate of microbal advisaries. If you can produce a strain of a disease that has a short, mild infection -- but out-competes the original, you've turned a lion into a house cat. For mosquitos, if we could replace the asian tiger variety with another that can't host malaria, we'd be set.
Also, more direct methods of mosquito control are useful. Many tropical communities now pay people to wander around town draining pools of stagnant water. Sure, you don't get them all, but you can drain enough that the mosquito population decreases dramatically. It's a continual effort, but uses no chemicals.
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Man... It was just a question. And, I thought, a timely one at that. By the way I'm an entomologist and I'm interested in what these readers think and less about what their opinion is.
how cleaning with bleach has bread super-bacteria in some hospitals that can be cultured on undiluted Clorox
You are a little off here.
The problem is that the use of non-bleach clearers are creating bacteria that are resistant to anything but bleach based cleaners.
Bleach is the best thing around to kill bacteria the way it works is to disolve the skin wall, no way to build up a resistance to that.