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 DDT’s use in malaria control; • To draw some historical lessons to provide guidance for future action.

9. Where I’m 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 Carson’s 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 Carson’s 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. Spraying cattle with DDT, Montana, 1947 Mother spraying DDT, New York, 1945 Corbis photo archives Corbis photo archives

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

35. Early environmentalist critique of DDT “Another such victory and I am undone”Cartoon by Bill Maudlin, 1962 Source: http://www.americaslibrary.gov/assets/aa/carson/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. 16.00 to 100.00 8.00 to 16.00 4.00 to 8.00 2.00 to 4.00 1.00 to 2.00 0.03 to 1.00 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 wasn’t 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. • DDT’s symbolic burden • DDT as a political football