Finally, some real help for Africa-the WHO sees the light

[j2k4]

Read all about it...

http://www.abc.net.au/news/newsitems...9/s1742413.htm

[lynx]

When compared to the obvious benefits, any minor adverse side effects are probably acceptable. Unfortunately I feel certain that there will be some who will see any such side effects as an opportunity to make money out of the DDT suppliers.

However, the big problem with malaria is not the mosquito, it is the people who are already infected with malaria. Mosquitos are just as common in other areas of the world and the only reason they don't transmit malaria is that they don't have sources (infected humans) to pick up the disease.

On it's own, this method is as doomed to failure as other methods which have been tried. If you kill 99% of mosquitos the other 1% are still just as capable of passing on the disease, and the surviving mosquitos are more likely to be resistant to DDT. Next attempt will only kill 98%, the attempt after that only 95%, and so on.

However, if at the same time you protect the majority (since 100% is not realistic) of the population with drugs, then the likelihood that one of the few surviving mosquitos will pick up the disease is dramatically reduced.

So while the idea certainly has merit, its success could be made much more effective by a determined effort to treat those already infected and prevent infection in others.

[Busyman™]

When compared to the obvious benefits, any minor adverse side effects are probably acceptable. Unfortunately I feel certain that there will be some who will see any such side effects as an opportunity to make money out of the DDT suppliers.

However, the big problem with malaria is not the mosquito, it is the people who are already infected with malaria. Mosquitos are just as common in other areas of the world and the only reason they don't transmit malaria is that they don't have sources (infected humans) to pick up the disease.

On it's own, this method is as doomed to failure as other methods which have been tried. If you kill 99% of mosquitos the other 1% are still just as capable of passing on the disease, and the surviving mosquitos are more likely to be resistant to DDT. Next attempt will only kill 98%, the attempt after that only 95%, and so on.

However, if at the same time you protect the majority (since 100% is not realistic) of the population with drugs, then the likelihood that one of the few surviving mosquitos will pick up the disease is dramatically reduced.

So while the idea certainly has merit, its success could be made much more effective by a determined effort to treat those already infected and prevent infection in others.

Good post.

[j2k4]

A bit more information and historical perspective, for what it's worth...I have emboldened sections which relate to DDT's effectiveness.


A lifesaving killer returns
By Jeff Jacoby
Tuesday, October 17, 2006


The 2006 Nobel laureates are in the spotlight, but a recent piece of news -- an announcement from the World Health Organization -- calls to mind a Nobel laureate of an earlier era.

When the Swiss chemist Paul Muller was awarded the prize in medicine in 1948, he was hailed "as a benefactor of mankind of such stature" that he would require "the humility of a saint" to inoculate himself against hubris. Fortunately, Muller was not given to arrogance. He described his great discovery as merely "a first foundation stone" in the "puzzling and apparently endless domain" of pest-borne plague. It had come as a surprise to him, he said modestly, to have discovered a chemical formula "so useful in the fight against diseases in human beings."


An Asian tiger mosquito, an invasive, disease-carrying pest, is shown in this 2001 file photo. The World Health Organization is poised to promote broader use of the pesticide DDT in the battle against malaria. Long banned in the United States because of environmental damage, DDT is used legally in a few impoverished countries to kill malaria-bearing mosquitoes.

"Useful" hardly began to describe it. As Time magazine noted, Muller's chemical "kills the mosquitoes that carry malaria, the flies that carry cholera, the lice that carry typhus, the fleas that carry the plague, the sand flies that carry kalaazar and other tropical disease." Thanks to his discovery, "the tropics are becoming safer places to live; because of it, typhus" -- a deadly scourge long associated with wars and disaster -- "was no serious threat in World War II."

The name of this miracle formula? Dichlorodiphenyltrichloroethane -- better known as DDT.

To anyone who grew up in the 1970s or 1980s, the notion that DDT was ever celebrated as a lifesaver might come as a shock. The very initials now seem sinister. Ever since Rachel Carson's "Silent Spring" was published in 1962, DDT has been stigmatized as a terrible environmental poison, more curse than cure.

In Carson's telling, DDT caused cancer and genetic damage in humans, and wreaked havoc not only on the insects it was intended to kill but on birds and other animals too. It was a poison that grew in concentration as it passed up the food chain, ultimately contaminating everything from eagles' eggs to mothers' milk. Carson recounted frightful tales of DDT's demonic power. "A housewife who abhorred spiders" sprayed her basement with DDT in August and September -- and was dead of "acute leukemia" by October. "A professional man who had his office in an old building" sprayed with DDT to get rid of cockroaches -- and landed in the hospital, hemorrhaging uncontrollably; eventually he too was dead of leukemia.

But in retrospect, such alarming anecdotes seem little more than urban legends. In the words of immunologist Amir Attaran, a fellow of the Royal Institute of International Affairs, "The scientific literature does not contain even one peer-reviewed, independently replicated study linking DDT exposures to any adverse health outcome" in human beings. Yet if Carson's science was shaky, her influence was undeniable. "Silent Spring" galvanized the emerging environmental movement and fed a rising hysteria about pesticides and other chemicals. Within a decade, DDT had been banned in the United States. Eventually every industrialized nation stopped using it. Under pressure from Western environmentalists and governments, DDT was widely suppressed in the Third World as well.

The results were catastrophic. As the most effective weapon ever deployed against mosquitoes and malaria was taken out of service, the mosquitoes and malaria returned. In Sri Lanka, for example, the spraying of houses with DDT had all but wiped out malaria, which shrank over a decade from 2.8 million cases and 7,300 deaths to 17 cases and no deaths. But when American funds to pay for DDT-based mosquito eradication dried up, malaria surged back, to half a million cases by 1969.

Today, the global malaria caseload stands at more than 300 million. The disease kills well over 1 million victims yearly -- some estimates run as high as 2.7 million -- and the vast majority of its victims are children in Africa. "Such a toll is scarcely comprehensible," Attaran and several colleagues have written. "To visualize it, imagine filling seven Boeing 747s with children, and then crashing them -- every day."

The demonizing of DDT, albeit with the best of motives, ended up causing tens of millions of deaths from malaria. Rarely has the law of unintended consequences operated with such lethality.

Now, at long last, that may change. In a historic shift, the WHO last month reversed its 30-year-old ban, and strongly endorsed the indoor use of DDT to control the mosquitoes that spread malaria. (The use of DDT on crops, which Carson had linked to the thinning of bird eggs, remains prohibited.) The WHO emphasized that DDT presents no health risk when sparingly applied to the inside walls of homes. And it urged environmentalist diehards to abandon their opposition to a proven lifesaver.

"I am here today to ask you, please help save African babies as you are helping to save the environment,” implored Arata Kochi, director of the WHO’s global malaria program. "African babies do not have a powerful movement ... to champion their well-being."

Sixty years after Paul Muller's great achievement was honored with a Nobel Prize, its potential may at long last be realized. A "silent spring" more hellish than anything Carson envisioned -- a million children dying needlessly every year -- may finally be coming to an end.

[Busyman™]

Basically you have to keep using DDT for it to continue to be effective.

Keep using....continue.

Makes sense.