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."
"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.
No, Mr. Green. Communism is just a red herring.
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!
If it's fact show some real studies. It's not fact it is COMPLETELY made up!
Here, have a few FACTS, you might learn something.
http://www.junkscience.com/ddtfaq.htm
DDT is a pesticide. It kills [some] insects. When you kill certain whole populations, it can throw the ecosystem out of whack. Unfortunately, that may be necessary to fight malaria. It may also be possible to use DDT in ways that fight malaria without killing 100% of certain insect populations.
That is, the mosquitos that DDT doesn't kill will stay away from the sprayed areas. You don't have to spray the whole countryside with DDT in order to stop malaria, you may be able to get away with just spraying the areas where people live (their walls). This will keep the pests away without killing them all, and therefore will not be so destructive to their ecosystem.
BTW, birds tend to flourish in the presence of DDT. If you kill the insects that spread avian diseases and eat the crops (which birds like to feed on), the birds become more abundant -- or at least those that don't feed on the insects you killed off.
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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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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.
Use the Firehose to mod down Second Life stories!
1) DDT did not decimate the ecosystem of Borneo
2) There were no outbreaks of plague or typhus. Every instance you find of someone saying this is someone retelling a trumped up story they heard. The cats were dropped because there was FEAR an outbreak would occur. It didn't.
3) The insect control measures in Borneo are today considered to have been a great success. The problem of malaria went away. Thousands of children lived who might otherwise have died, and as I mentioned, there was no outbreak of plague or typhus.
4) Sorry, I just don't take USAID's position on DDT seriously. They have in the past shown themselves to be tools of of the anti-DDT environmental lobby.
Education is a better safeguard of liberty than a standing army.
Edward Everett (1794 - 1865)
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.