reply to Dr. Josť Luis Solleiro
What is wrong with defending DDT? Is there any peer reviewed, sceintific
evidence of its harm to humans? I have searched the literature and cannot
find any butdon't take the word of an economist, check what the authors
have to say and follow their footnotes. Or for that matter, one of the
authors is, I believe on this list. In any case, I will send him a copy
of Dr Solleiro' s note and my reply.
I cannot think of a more perfect example than DDT. Read my posted piece
on DDT Saves Lives (click in below to webpage) and see hon many hundereds
of millions of people were exposed to sizeable doses of DDT: in the
anti-typhus campaign in Southern Europe during World War II (it was not
merely sprayed on, it was blown into their clothing and on to them so that
they did not have to experience the indignity of having to disrobe), ,ll
those released from concentration camps and many of the troops,. After the
War, we have the malaria spraymen, the workers in DDT factories, farmers
who used it, those who were exposed to it in malaria control programs etc.
etc. etc. Many of these groups are clearly definable and have been studied
over the decades. Certainly, it has been long enough for any signs of
harm to emerge. Name anything that has been so completely studied and in
which so little was found.
On the other side of the coin, let us look at how many hundred of millions
of lives that have been saved because of DDT. Check among other sources,
the National Academy of Sciences reports that I cite in my piece. More
tragically, let us look at the lives being lost today because of the
difficulties form getting DDT and the many more which would be lost if it
were banned completely. Let us face fact, no matter what rhetoric
Greenpeace others used, it is clear that lives of African children simply
do not count in their moral equation. (On the trade-off between African
lives and elephants, I was categorically told by an environemtalist, that
they worry about African lives, there were plenty more where they came
from. He added that one hundred from now, fewer elephants would make a big
difference but nobody would notice fewer Africans.) Go read the articles
in Lancet plus the one in Nature Medicine and others that I sent,
including my owb, Let Us Spray (also posted which includes a reference to
an important article in the BMJ). These articles note that the so-called
precautionary principle is being used in a way in which theoretical but
thus far disproved theories of harm to European and North American
children trumps the very real harm to African and other children of the
malarial tropics. Or is it merely to protect raptors? If so let them tell
us their trade-offs, how many African children have to die for each raptor
saved? No matter how you try to sugar coat the rhetoric, this is
neo-colonialism and racism, pure and simple. Somehow, those pursuing this
agenda have gotten by with name calling and labeling others but have
escaped what should be seen as an accurate designation.
The response by Dr. Josť Luis Solleiro shows precisely why we have to
address the DDT even if the luddites did not keep raising it as an example
of the horrible outcome of something that once seemed benign. It shows
how you can so successfully demonize a technology and so brainwash a
that even decent defenders of GM foods like Dr. Solleiro want to avoid the
DDT issue when the facts are overwhelmingly on our side. Greenpeace is
trying to do to GM foods what they and their predecessors have done to DDT.
On final note, even though the DDT issue is relevant to this news group
for the reasons given above, it should also have its own news group. The
attempt to ban DDT and the other so-called POPs, is so blatantly racist,
so harmful to the poorest and most vulnerable people on this plant, that
anyone with a scintilla of decency, should be totally outraged by it. I
still have faith that the vast majority of the people in developed
countries would oppose this action if they were fully informed. That they
don't shows the effectiveness of the propaganda machine of the
anti-technology luddites. People in this newsgroup and those of similar
persuasion have tried to avoid vituperation in favor of intelligent,
scientific arguments unlike those who parade around with signs tha read
WTO Kills or refer to the "death culture of science." Without desending
to their level, at some point, we are going to have to say that the
machinations that result in such a horrendous toll in human life and human
well-being are evil and should be so labeled. Any lesser designation is
not self-restraint on our part, it is dishonest.
At 06:39 PM 7/26/2000 -0500, Dr. Josť Luis Solleiro wrote:
>I think that argumentation should be more comprehensive, because malaria
>just one disease. Analysis should be made on the impacts of DDT on health,
>in general. I agree that we should have strong arguments to those of
>Greenpeace, but not based on defending DDT.
Date: Jul 26 2000 19:42:43 EDT
Subject: RE: Three articles and an editorial in The Lancet
I think that argumentation should be more comprehensive, because malaria
is just one disease. Analysis should be made on the impacts of DDT on
health, in general. I agree that we should have strong arguments to those
of Greenpeace, but not based on defending DDT.
If you would take the time to read the articles in Lancet or any of a
number of other articles in the peer-reviewed medical literature, you will
find that there isessentially no human health threat that has ever been
identified coming from DDT exposure, or to exposure of its breakdown
products, DDD and DDE.
After decades of use and millions of human exposures through both high,
accute doses and low, chronic, long-term exposures, the anti-DDT activists
have been reduced to claiming potential endocrine disruption from the very
weak oestrogenic properties of DDT/DDD/DDE. If you don't believe me, take
included below from the July 22, 2000 Lancet on DDT's toxicity and charges
that DDT is harmful to human health. It boils it all down quite nicely:
DDT is one of the safest pesticides know as far human health is concerned.
DDT should not be banned worldwide because nothing works as well, and
nothing is nearly as cheap. Banning DDT will certainly result in millions
of needless deaths. Remember, 300 million people are infected with malaria
every year, and one million (mostly children) die from it annually. The
theoretical health impacts from spraying the inside walls of homes (no one
is arguing for a return to DDT use in agriculture or for widespread
environmental spraying, just prescriptive use inside homes to prevent
malaria) is inarguably less than the very real threat of dying or being
severly disabled by a malaria.
Also, the number of malaria cases is skyrocketing and the rate of increase
in malaria cases is accelerating which is why the World Health
Organization and the UN Committee on Malaria have both vigorously defended
DDT use and retention as a critical anti-malarial tool.
How Toxic is DDT
Lancet, vol. 356, July 22, 2000, pages 267-268
In many regions of the world, especially Europe and the USA, people have
forgotten what it is like to have endemic malaria. One of the most
important reasons why these regions are no longer endemic for malaria is
the use of DDT (dichlorodiphenyltrichloroethane) after the 1939-45 war.
When DDT was first used in Naples in January, 1944, 1=B73 million
civilians were dusted, and even in the midst of winter the incidence of
typhus fell sharply. Subsequently, many allied troops and refugees were
dusted or wore clothes impregnated with DDT to protect against vermin and
typhus. Since DDT turned out to
be a highly potent contact insecticide, its potential in the control of
malaria was soon recognised. The spraying of houses with DDT led to
striking reductions in mosquito counts indoors and, subsequently, in cases
of malaria. Reports of such findings, with huge economic benefits, came
from Europe, Africa, the USA, India, Sri Lanka, and South America.
The start of the decline, by the early 1960s, of the use of DDT in Europe
and the USA, was due partly to the introduction of other insecticides but
was also hastened by the recognition that DDT and its metabolite DDE
(dichlorodiphenyl- dichloroethylene) persisted in the environment and
might harm some species of wildlife.
Much of the environmental concern arose as a result of the general use of
DDT for the control of many pests and because DDT was not distinguished
from other insecticides, but there has also been concern over its direct
effects on human beings. DDT is prohibited in many industrialised
countries, and the United Nations Environmental Programme is starting
negotiations for a global ban. In today=92s Lancet
D R Roberts and colleagues argue for the continued use of DDT, on grounds
of its value for malaria control and its safety. The early toxicological
information on DDT was very reassuring; it seemed that acute risks to
health were small. If the huge amounts of DDT used are taken into account,
the safety record for human
beings is extremely good. In the 1940s many people were deliberately
exposed to high concentrations of DDT through dusting programmes or
impregnation of clothes, without any apparent ill effect.3
There are probably few other chemicals that have been studied in as much
depth as has DDT, experimentally or in human beings. 3
It quickly became clear that the dermal toxicity of dry DDT was very low,
but even the oral toxicity
depended on the composition of the diet. By contrast dieldrin caused
poisoning of sprayers in many malaria-control programmes 2 and is equally
toxic by oral and dermal routes, the acute toxicity to rats being more
than three times that of DDT.
Ingestion of DDT, even when repeated, by volunteers or people attempting
suicide has indicated low lethality, and large acute exposures can lead to
vomiting, with ejection of the chemical. The earliest symptoms are
hyperaesthesia of the mouth, followed by paraesthesia of the tongue,
dizziness, tremors, and vomiting. Few toxicological effects due to
inhalation of DDT have been reported. Some deaths attributed to DDT have
been due to mixtures with other chemicals or solvents.
Dermatitis in workers expose= d to DDT was also probably due to solvents.
Thus with acute or high-level
exposure, DDT is probably safer than many other chemicals. What concerns
most people is chronic exposure to DDT. Evidence for any paraesthesia,
headaches or dizziness, or changes in liver-function tests in workers who
worked with or used DDT are very rare despite the presence of
significantly raised serum concentrations of DDT or DDE. 3
Many of those workers investigated have been sprayers in antimalarial
programmes. As exemplified by malaria control in Natal, 46 serum DDT has
been significantly higher in sprayers and members of sprayed households
than in control populations, and the chemical may be passed in the milk to
infants, but associated toxicity has not been proven. Of great concern
has been the potential association between cancer incidence and exposure
to DDT, especially via an environmental route. Studies of the mutagenicity
of DDT and its significance in human beings have not yielded clear results.
Although DDT acts as a hepatocarcinogen at high doses in some strains of
mice, there is no convincing
evidence for this effect in human beings.
A preliminary study of death= s among Sardinian men who had worked with
DDT in a malaria-eradication campaign in the 1940s showed a significantly
increased risk of liver and biliary-tract cancers among those workers (PMR
2=B710, 95% CI 1=B7173=B747), but the effect was also found among
non-exposed workers (PMR 2=B728, 1=B7433=B745).
In fact, there is no strong evidence for any associated cancer risk among
people exposed to DDT except perhaps among workers who may have been
exposed to DDT plus other chemicals, for whom there was an increased risk
of pancreatic cancer. 8
There has been a debate, driven by in-vitro studies, about a possible link
between environmental exposure to DDT and breast cancer in the USA,
perhaps due to increased levels of oestrogen receptors, but the overall
evidence is weak. No increased incidence of breast cancer was found among
North Vietnamese women who had raised serum DDT concentrations after
exposure to antimalarial sprays.10
Although there is little evidence that chronic low-level exposure to DDT
produces serious deleterious effects, the current debate on potential
=93endocrine disruptors=94 has brought up the possibility of other
potential toxicological effects. DDE has been found to be an antiandrogen
11 and, in addition to its proposed link to breast cancer, DDT is commonly
cited as having oestrogenic effects. In one study of the most heavily
exposed workers in a DDT factory, there seemed to be no effect on their
ability to father children.
In interpreting possible toxic hormonal effects of DDT, it should be noted
that in-vitro studies often employ the o,p-isomer of DDT, which does have
weak oestrogenicity in vivo but has constituted only a tiny percentage of
the total DDT used. Nevertheless there has been a proposal that exposure
of mice to very low
concentrations of DDT in utero or at certain perinatal stages could have
subtle developmental influences. 12
This idea or its applicability to human beings would be very difficult to
disprove completely. In summary, DDT can cause many toxicological effects
but the effects on human beings at likely exposure levels seem to be very
slight. However, the perceived rather than the calculated risks from DDT
use are an important consideration in maintaining public confidence. Thus
it would seem prudent that if its use was continued for antimalarial
campaigns and the benefits of use outweigh the risks, tight control should
continue and the effects of spraying DDT should be closely monitored. What
has not been discussed here, though, is the environmental issue of any
detrimental effect on wildlife.
A G Smith
MRC Toxicology Unit, Leicester University, Leicester LE1 9HN, UK
1 West TF, Campbell GA. DDT; the synthetic insecticide. London: Chapman
and Hall Ltd, 1946.
2 Hayes WJ. Introduction. In: Hayes WJ, Laws ER, eds. Handbook of
pesticide toxicology San Diego: Academic Press, 1991: 137.
3 Smith AG. Chlorinated hydrocarbon insecticides. In: Hayes EJ, Laws, eds.
Handbook of pesticide toxicology. San Diego: Academic Press. 1991: 731915.
4 Bouwman H, Coopan RM, Both MJ, Becker PJ. Serum levels of DDT and liver
function of malaria control personnel. S Afr Med J 1991; 79: 32629.
5 Bouwman H, Coopan RM, Becker PJ, Ngxongo S. Malaria control and levels
of DDT in serum of two populations in KwaZulu. J Toxicol Environ Health
1991; 33: 14155.
6 Bouwman H, Becker PJ, Coopan RM, Reinecke AJ. Transfer of DDT used in
malaria control to infants via breast milk. Bull WHO 1992; 70: 241250.
7 Cocco P, Blair A, Congia P, et al. Proportional mortality of
dichloro-diphenyl- trichloroethane (DDT) workers: a preliminary report.
Arch Environ Health 1997; 52: 299303.
8 Garabrant DH, Held J, Langholz B, Peters JM, Mack TM. DDT and related
compounds and risk of pancreatic cancer. J Natl Cancer Inst 1992; 84:
9 Key T, Reeves G. Organochlorines in the environment and breast cancer.
The data so far produced provide reassurance rather than anxiety. BMJ
1994; 308: 152021.
10 Schecter A, Toniolo P, Dai LC, Thuy LTB, Wolff MS. Blood levels of DDT
and breast cancer risk among women living in the North of Vietnam. Arch
Environ Contamin Toxicol 1997; 33: 453456.
11 Kelce WR, Christy RS, Laws SC, Gray LE, Kemppaven JA, Wilson EM.
Persistent DDT metabolite p,p -DDE is a potent androgen receptor
antagonist. Nature 1995; 375: 58185.
12 Eriksson P, Ahlbom J, Fredriksson A. Exposure to DDT during a defined
period in neonatal life induces permanent changes in brain muscarinic
receptors and behaviour in adult mice. Brain Res 1992; 582:
Alex A. Avery
Director of Research and Education
Center for Global Food Issues
P.O. Box 202
Churchville, VA 24421
fax: (540) 337-8593
Date: Jul 27 2000 11:57:34 EDT
From: Tom DeGregori
Subject: (No Subject)
Special Focus on MALARIA!
Malaria, the age-old, potentially fatal disease transmitted by mosquitoes,
is now high on the agenda of the biomedical community. For free access on
all the latest research and developments, visit http://medicine.nature.com
Nature Magazine im its weekly email notice of contents has included the
following note. The link to a Nature Medicine article that I sent out is
in this special focus. I recommend the entire section. The following
magazine cover note on the articles and on the commentary on DDT and
Malaria control is as follows:
As outlined above by Mats Wahlgren, the magnitude of the malaria problem
is the reason that Nature Medicine has chosen to pay special attention to
this disease and produce a website presenting the latest biomedical
research directed at combating malaria.
We are pleased to present readers with a selection of the most-recent and
best scientific papers and News & Views articles on malaria research
published in our journal and in Nature. In addition, this website contains
a new Commentary article setting out the reasons why the United Nations
Environment Programme should re-think its proposed ban on the use of DDT
insecticide in malaria-endemic countries, plus a status report on malaria
vaccine development presented at the US National Institutes of Health
this spring. An update on the effort to sequence the Plasmodium falciparum
genome is available in the Research News section, along with summaries of
malaria research papers appearing in other, non-Nature journals. The news
section contains stories outlining the political and financial war being
waged against the disease.
We hope you enjoy learning more about malaria from this site andwe welcome
your feedback via email@example.com
Those interested in the website on malaria should I assume to the
following: "Correspondence should be addressed to M.W.; email:
Thomas R. DeGregori, Ph.D.
Professor of Economics
Department of Economics
University of Houston
Houston, Texas 77204-5882
Ph. 001 - 1 - 713 743-3838
Fax 001 - 1 - 713 743-3798
Web homepage http://www.uh.edu/~trdegreg