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DDT and Malaria Control: Public Health vs. Environmentalism?

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DDT and Malaria Control: Public Health vs. Environmentalism? Eric D. Carter, Ph.D. Geography Anthropology Department TEC-154, Spring 2011 – PowerPoint PPT presentation

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Title: DDT and Malaria Control: Public Health vs. Environmentalism?


1
DDT and Malaria Control Public Health vs.
Environmentalism?
  • Eric D. Carter, Ph.D. Geography
  • Anthropology Department
  • TEC-154, Spring 2011

2
Malaria Global Impact
  • Malaria today is in the top 3 of causes of
    mortality by infectious disease (HIV/AIDS, TB)
  • 300-500 million cases of malaria each year
  • 2000 children per day die of malaria
  • Impacts economic development

3
WHO map of malaria transmission risk (2003)
4
WHO map of estimated incidence of clinical
malaria episodes (2004)
5
Transmission Cycle of Malaria
  • Vector-borne disease
  • Agent Plasmodium parasite
  • 2 major species P. falciparum, P. vivax, etc.
  • Vector Anopheles mosquito
  • 400 species 40 are efficient vectors

Female A. gambiae mosquito taking blood meal
6
Malaria Long-term trends
  • Global malaria incidence declined dramatically
    from 1945 to late 1960s.
  • WHO global eradication program (using DDT)
  • Resurgence of malaria starting in 1970s

World Health Organization, 1999
7
DDT and Malaria Control
  • DDT was once the most important weapon in malaria
    control.
  • Whether DDT should be used remains a
    controversial issue.
  • The controversy seems to pit environmentalists
    (anti-DDT) against some public health advocates
    (pro-DDT).

8
Goals for Today
  • To shed some light on the history of DDT's use in
    malaria eradication
  • To examine the debate over DDTs use in malaria
    control
  • To draw some historical lessons to provide
    guidance for future action.

9
Where Im coming from
10
A brief history of malaria eradication
11
Malaria Control before DDT
  • DDT arrives on the scene around 1945
  • What technologies were used in malaria control
    before?
  • Mainly, methods of environmental sanitation
    aimed at mosquito breeding areas.

12
Malaria Control before DDT
Drainage work in Northwest Argentina
13
Malaria Control Before DDT
Drainage work in southern U.S. (Tennessee Valley
Authority)
14
Malaria Control before DDT
Stream shading (biological tunnels) in Argentina
Application of larvicides (Paris green copper
aceto arsenate) in TVA projects
15
Malaria Control Before DDT
Manipulation of water levels in TVA reservoirs
16
Malaria Control Before DDT
Topographic mapping, frequent environmental
monitoring
17
Malaria Control Before DDT
  • Technologies (e.g. drainage) associated with a
    particular social and spatial organization of
    labor.
  • The technologies do not stand alone
  • New technologies cannot be simply plugged in to
    existing models and systems
  • Focus pre-DDT unpredictable, disorderly and
    dynamic nature (think like a mosquito)
  • Focus post-DDT homogenous, stable, predictable
    human habitats (i.e. houses)

18
DDT and Malaria Control
  • Why was DDT a revolutionary technology for
    malaria control?
  • Simplicity
  • Potency
  • Residual action
  • Safety
  • Cost effectiveness
  • Transferability

Anti-Malaria Spraying in Guyana
19
DDT and Malaria Eradication
  • How did the malaria eradication program work?
  • Define a territory
  • Spray every house in the area with DDT twice a
    year (indoor residual spraying)
  • Break transmission chain by eliminating
    mosquitoes
  • Treat remaining malaria cases with
    pharmaceuticals
  • Key eliminate mosquitoes long enough to wipe out
    the parasite from a human population

20
Malaria Eradication in Argentina
  • Backing from the Perón government
  • Existing public health infrastructure was good
  • Involved other technologies
  • Military-style campaign

Malaria Eradication Brigades, 1947
21
Malaria Eradication in Argentina
  • Immediate results
  • Between Sept 1947 and April 1948
  • 170,000 houses sprayed
  • 43 tons of pure DDT
  • 1 million liters of gasoline
  • Malaria incidence dropped by about 96 percent in
    that time.

One Less Enemy Peronist Propaganda
22
Global Eradication Campaign
  • Success in Argentina, US, Venezuela, led to Pan
    American Health Organization effort
  • Led by Fred L. Soper, an American epidemiologist,
    and Carlos Alvarado, from Argentina
  • Strategy adopted by WHO for global malaria
    eradication program in 1955

Fred L. Soper
23
Logic of Malaria Eradication
  • Abundant faith in science and technology
  • Reductionist
  • Technocratic
  • Military logistics
  • Benefit-cost analysis
  • Modernization theory
  • Technology transfer
  • Foreign aid
  • Cold War context
  • Cultural change

India Malaria Eradication Campaign Poster, ca.
1960
24
Global distribution of malaria, 1946-1994
  • Source Sachs and Malaney (2002)

25
Rise and Fall of Eradication
  • 1955-1969 WHO Malaria Eradication program
  • Latin America Caribbean, Asia
  • Very effective in some places
  • Sri Lanka 3 million cases (1945) to 29 (1964)
  • Mid-1960s problems
  • Rise of environmentalism
  • Rachel Carsons Silent Spring (1962)
  • 1969 WHO abandons eradication strategy

26
The DDT Debate
27
The DDT Debate
  • Should the use of DDT be banned completely?
  • DDT was banned in the US in 1972 and in many
    other countries since.
  • It was almost banned completely by international
    treaty in 2004 (POPs persistent organic
    pollutants)
  • A dilemma DDT may save lives, but it is also
    hazardous.
  • Highly polemical debate

28
The Malaria Clock A Green Eco-imperialist
Legacy of Death
  • Junkscience.com

29
The Dangers of DDT
  • Begins with Rachel Carsons book Silent Spring
    (1962)
  • Sparked the modern environmental movement
  • Compelling case against DDT and other POPs

Rachel Carson
30
The Dangers of DDT
  • DDT disrupts the endocrine system and
    bioaccumulates up the food chain
  • Impact on birds
  • Robins, bald eagles, peregrine falcons

Rachel Carson
31
The Dangers of DDT
  • Probably carcinogenic in humans
  • Broader critique of modern technology disrupting
    the balance of nature ecology becomes
    political
  • Use of DDT and other pesticides was out of
    control by the 1960s

Rachel Carson
32
Uses of DDT in the 1950s 1960s
33
Mother spraying DDT, New York, 1945
Spraying cattle with DDT, Montana, 1947
Corbis photo archives
  • Corbis photo archives

34
Advertisement for Penn Salt Chemicals
  • Time Magazine, June 30, 1947.
  • Source http//www.someareboojums.org/blog/

35
Another such victory and I am undoneCartoon by
Bill Maudlin, 1962
Early environmentalist critique of DDT
  • Source http//www.americaslibrary.gov/assets/aa/c
    arson/aa_carson_consequenc_2_e.jpg

36
The Dangers of DDT
  • Carson was dismayed by the indiscriminate use of
    DDT and other POPs
  • Public health advocates argue that DDT spraying
    for malaria control is different

37
kilograms
Treat one house for malaria control in a year
Treat one acre of cotton in a growing season
Based on estimates for Guyana DR Roberts, et al.
(1997)
38
DDT Resistance
  • Another argument against DDT is that insects
    eventually develop resistance against it.
  • This is true and the mechanisms are well
    understood natural selection, selective pressure
  • DDT resistance is not the main reason for the
    failure of the global malaria eradication program
  • And, DDT has proved to be effective in many
    places.

39
Annual Parasite Indexes per 1,000 Source DR
Roberts, et al. (1997)
40
Malaria Cases vs. Households Sprayed with
Insecticide, Mexico, 1959-1993
  • Source Packard, The Making of a Tropical Disease

41
Conclusions
42
Conclusions
  • DDT use for malaria control is appropriate in
    some places and not in others.
  • Diverse and uneven geography of risk
  • Do we need a universal policy on DDT?
  • Assessments of acceptable risk depend on local
    circumstances

43
Conclusions
  • DDT is not a magic bullet. In fact, there is no
    magic bullet.
  • The technology of DDT was just one ingredient in
    malaria eradication
  • Where eradication failed, it wasnt because DDT
    failed
  • Public health infrastructure
  • Adequate and sustained levels of funding
  • Political support
  • Need to de-emphasize technology in discussing
    malaria control options

44
Conclusions
  • Politically charged, morality-tale thinking
    distracts us from making real achievements in
    combating malaria.
  • DDTs symbolic burden
  • DDT as a political football

45
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