The DDT Ban Myth

Several anti-environmentalists have claimed that public concern over the effects of DDT after the publication of Rachel Carson's Silent Spring led to a ban on the pesticide in some third world countries in the 1960s.  This ban, it is claimed, led to a resurgence in malaria, resulting in thousands of deaths.  But in accounts of the war on malaria, such as in Laurie Garrett's The Coming Plague,  it is clear that the suspension of spraying programs was unrelated to any environmental concerns.  In fact, DDT continued to be the insecticide of choice in the battle against malaria as recently as 1994, some 30 years after the alleged ban, in areas where it was still effective (Curtis). Before considering what actually happened, let's see how some anti-environmentalists described the alleged ban.

This is how Elizabeth Whelan (Toxic Terror, page 69) described events:

Why was there an increase in malaria in Ceylon [now called Sri Lanka] after 1964?  It is clear that the effects of Silent Spring was not limited to the United States.  Following the publication of this book, the use of DDT was discontinued in Ceylon.  Epidemic conditions reappeared and it has been estimated that between 1968 and 1969 "considerably more than two million cases occurred," all related to the campaign against DDT.

Here is how Dixy Lee Ray (with Lou Guzzo) described events (Trashing the Planet, page 69) [note:  Ray has the timing wrong, the spraying was stopped in 1964, not the late 60s]:

Public health statistics from Sri Lanka testify to the effectiveness of the spraying program.  In 1948, before the use of DDT, there were 2.8 million cases of malaria.  By 1963, there were only 17.  Low levels of infection continued until the late 1960s, when the attacks on DDT in the U.S. convinced officials to suspend spraying.  In 1968, there were one million cases of malaria.  In 1969, the number reached 2.5 million, back to the pre-DDT levels.  Moreover, by 1972, the largely unsubstantiated charges against DDT in the United States had a worldwide effect.  In 1970, of two billion people living in malaria regions, 79 percent were protected and the expectation was that malaria would be eradicated.  Six years after the United States banned DDT, there were 800 million cases of malaria and 8.2 million deaths per year.  Even worse, because eradication programs were halted at a critical time, resistant malaria is now widespread and travelers could take it home.

Here is the version of Joseph L. Bast, Peter J. Hill. and Richard C. Rue (Eco-Sanity, page 100):

But probably the most remarkable demonstration of the health-preserving powers of pesticides was the use of DDT to kill maria-carrying mosquitoes.  Thanks to DDT, countries such as Zanzibar (an island off the east coast of Africa) reduced the percentage of their populations infected with malaria from 70 percent in 1958 to under 5 percent in 1964.  Then, the DDT spraying program was suspended, and by 1984 the malaria rate was back up to 50 to 60 percent . . .It is probably fair to say that Zanzibar and other African countries would not have suspended DDT spraying if environmentalists had not claimed, without evidence, that DDT posed a significant risk to human health.  DDT is still used to combat malaria in some parts of the world, and the decision to suspend spraying in Zanzibar and other areas reflected the judgments of health officials and political leaders as well as environmentalists.  Still, the environmental movement must take partial responsibility for halting the use of what many health experts considered to be the greatest lifesaving chemical ever discovered--so great that its inventor, Dr. Paul Muller, was awarded the Nobel Prize in medicine in 1948.

And, most recently by Michael Sanera and Jane E. Shaw in Facts not Fear (pages 202 to 203) (Note::  the book lists the halt in spraying as a consequence of the 1972 US ban on DDT, given the timing this is clearly impossible):

In at least one country, Sri Lanka, a DDT spraying program, which had virtually eliminated malaria in Sri Lanka, was stopped.  When Sri Lanka stopped using DDT, the number of malaria cases rose again to 2.5 million in the years 1968-9.

There were suspensions in the spraying programs, but they were not the result of any "environmental hysteria".  To understand what actually happened, it is necessary to learn about the realities of pesticide use. One of the major problems with using pesticides is that insect populations soon develop resistance to the chemicals.  Insects resistant to DDT began appearing one year after its first public health use (Garrett, page 50).  As new insecticides were introduced, resistance to them also developed.  Much of Silent Spring is a cataloging of reports of resistance to insecticides. With the problem of mosquito resistance to DDT in mind, a plan to eradicate malaria was developed--several years of spraying, accompanied by treating patients with anti-malaria drugs,  would be followed by several years of monitoring.  Here is how Paul Russell, who would head the eradication effort, explained it in 1956 (Quoted in Garrett, page 48):

Generally, it takes four years of spraying and four years of surveillance to make sure of three consecutive years of no mosquito transmission in an area.  After that, normal health department activities can be depended upon to deal with occasional introduced cases. . . .  Eradication can be pushed through in a community in a period of eight to ten years, with not more than four to six years of actual spraying, without much danger of resistance.  But if countries, due to lack of funds, have to proceed slowly, resistance is almost certain to appear and eradication will become economically impossible.  Time is of the essence [his emphasis] because DDT resistance has appeared in six or seven years.

Incredible as it might seem, while public health officials were cautiously limiting the usage of DDT, it was being used in increasing amounts in agriculture, especially on cotton, a cash crop (Chapin & Wasserstrom).  This heavy use led to resistance among malaria carrying mosquitoes throughout the tropics. In this instance, the unwise use of DDT, rather than improving life, actually resulted in a resurgence of malaria.  According to Chapin & Wasserstrom (page 183) "Correlating the use of DDT in El Salvador with renewed malaria transmission, it can be estimated that at current rates each kilo of insecticide added to the environment will generate 105 new cases of malaria." 

 Not surprisingly, anti-environmentalists ignore or downplay the importance of insect resistance.  There is no mention of the problem in Trashing the Planet, Eco-Sanity or Facts not Fear.  Toxic Terror, which has a twenty six page chapter on "The DDT Debate", devotes just one paragraph to the issue.  There is no mention of the impact of DDT resistance on the war against malaria. 

There were a number of other problems in addition to insect resistance to DDT and other insecticides.  The heavy use of anti-malaria drugs started to produce microbes resistant to them. Non insecticide control measures that had greatly reduced the presence of malaria in many areas were discontinued when DDT arrived (Chapin & Wasserstrom).  There was a chronic lack of funds. Many countries had to abandon their control efforts, or they diverted funds to other areas when the number of cases of malaria had been reduced to a low level.  The United States bankrolled the eradication program starting in 1958, with the assurance that it would only take five years.  When the five years was up, the funding was cut off, even though it appeared that the eradication program was working (Garrett). This cut off of funds occurred just before the alleged bans went into effect.  Political turmoil also might have had an effect.  1964 was a year of major political turmoil in Zanzibar, the country used as an example in Eco-Sanity.  The country gained independence in December 1963, there was a bloody revolt in January 1964, and later that year the country joined with the much lager mainland country of Tanganyika to form the country of Tanzania (Kaplan).  Any of these events could have disrupted the malaria control program.  

The eradication program ended not because of any environmental concerns, but because it did not work.  The mosquitoes had grown resistant to insecticides, and the microorganisms that cause malaria had become resistant to the drugs used against them.  In many areas the numbers of cases of malaria greatly exceeded what it was before the effort was started.  If events had been different, if DDT had not been used heavily in agriculture and there was no shortage of funds the outcome might have been different.  Malaria might have joined smallpox as a disease that had been eliminated from the face of the earth.  Unfortunately, such was not the case.  As early as 1967 it was clear that the effort had failed, and in 1972 the official policy shifted from eradication to control of malaria.

Commentary

DDT was not banned in any developed country till the 1970s (Curtis).  It was not banned in the United States, that hotbed of "environmental hysteria", until 1972, and even then there were exemptions for health emergencies and some agricultural uses.  The anti-environmental claim that some third world countries that were fighting malaria banned the pesticide back in 1964 stretches our credulity, to say the least.  Certainly such a ban would generate a great deal of press coverage, as well as protests from the affected citizens and the international agencies that were trying to eradicate malaria.  But the anti-environmentalists produce no such evidence.  The only "proof" that is offered that the suspensions were related to environmental concerns was that they occurred after the publication of Silent Spring. But this is a post hoc ergo propter hoc (after this, therefore because of it) fallacy, no cause and effect was established.  None of the authors who repeated this claim appear to have considered that there might be an alternative explanation for the halting of the spraying program.  Rather than causing deaths, the cautions in Silent Spring about the indiscriminate use of pesticides could have saved many lives.

References

Bast, Joseph l., Peter J. Hill, and Richard C. Rue, Eco-Sanity: A common-Sense Guide to Environmentalism, Madison Books, 1994.

Carson, Rachel, Silent Spring, Houghton Mifflin Company, 1962.

Chapin, Georgeanne & Robert Wasserstrom, "Agricultural production and malaria resurgence in Central America and India", Nature, Vol. 293, 1981, pages 181 to 185.   

Curtis, C. F., "Should DDT continue to be recommended for malaria vector control?", Medical and Veterinary Entomology, Vol. 8, 1994, pages 107-112

Garrett, Laurie,  The Coming Plague: Newly Emerging Diseases in a World Out of Balance, Penguin Books, 1994.

Kaplan, Irving (editor), Tanzania, a Country Study, The American University, 1978.

Ray, Dixy Lee & Lou Guzzo, Trashing the Planet: How Science Can Help Us Deal with Acid Rain, Depletion of the Ozone, and Nuclear Waste (Among Other Things), HarperPerennial, 1990.

Sanera, Michael and Jane S. Shaw, Facts not Fear:  A Parent's Guide to Teaching Children About the Environment, Regnery Publishing, Inc., 1996. Now in a second edition.

Whelan, Elizabeth M., Toxic Terror, Jameson Books, 1985.

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Additional reading

NEW Putting Myths to Bed by Dr Alan Lymbery is the best responce I have seen to the DDT myth makers:

NEW More DDT myths

NEW John Quiggin notes that the far right is still recycling nonsence about DDT UPDATE Quiggin has added a clarification of his views on DDT.

NEW In DDT, Eggshells, and Me Ronald Bailey, a leading "brownlash" author breaks wih the useual "junk science" dogma and shows that DDT and its metabolites did harm bird populations.  For more on the topic see Effects of DDT on Birds:  Does Dixy Know Something the Experts Do Not?

NEW DDT and Other Chlorine-Based Chemicals were Banned for a Reason from Exposing the Right

"Malaria, Mosquitoes and DDT" by Anne Platt McGinn, WorldWatch May/June 2002, pages 10-16.

Mosquito:  A Natural History of our Most Persistent and Deadly Foe, by Andrew Spielman, Sc. D., and Michael D'Antonio, Hyperion, 2001

anopheles.com

The history of malaria

Whatever Happened to Malaria Eradication?

See Tim Callahan's  "Environmentalists Cause Malaria! (And Other Myths of the "Wise Use" Movement}" The Humanist January/February 1995, pp 10-15 for more on Dixy Lee Ray and malaria.

See "Do Environmentalists Cause Malaria?" in PR Watch's Panic Attack for more on Elizabeth Whelan, DDT and malaria.

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Written by Jim Norton

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