American Journal of Public Health | November 2008, Vol 98, No. 11 1940 | Public Health Then and Now | Peer Reviewed | O'Shaughnessy program, especially in the remote areas of the world where control efforts would be most difficult. A report written by members of the WHO antimalarial team working in the Malaysian state of Sarawak, on the island of Bor- neo, provides an example of the techniques used to conduct an indoor residual spraying cam- paign in a remote, heavily for- ested area, typical of many areas of the world where malaria was endemic. 7 During the initial cam- paign, both DDT and another in- secticide, BHC (benzene hexachloride), were sprayed in Sarawak between 1952 and 1955. Spraying only occurred in- side dwellings, which, for each village, consisted of a “long- house,” a large thatched-roof building that could house as many as 100 families. Before ap- plication, DDT was mixed as a 75% solution in water and then applied on walls and under beds at a concentration of 2 g/m 2 . This application left a visible resi- due of white spots on surfaces. 8 The primary intent was to cover walls on which mosquitoes alit with enough residue to kill them before they could transfer IN SEPTEMBER 2006, THE World Health Organization (WHO) issued a statement that recommended wider use of di- chlorodiphenyltrichloroethane (DDT) through indoor residual spraying to reduce the preva- lence of malaria. Among its rea- sons for reestablishing a malaria control effort first administered in the 1950s, WHO cited DDT’s potential to substantially reduce malaria because of its low cost, long-lasting action and ability to kill mosquitoes that land on sprayed surfaces. 1 Given its 40- year history as a substance banned for agricultural use by many countries because of its persistence in the environment and potential for ecological harm, it is not surprising that WHO’s statement has reinvigo- rated the debate over the use of DDT to control malaria. 2 Al- though the debate involves a va- riety of factors, it is centered on the balance between DDT’s posi- tive public health effects and its harmful ecological effects. Even the use of DDT for malaria con- trol, however, had some unfore- seen negative results. To ground the current debate on lessons ⏐ PUBLIC HEALTH THEN AND NOW ⏐ | Patrick T. O’Shaughnessy, PhD from the past, I review the his- tory of DDT in the context of the unintended consequences associ- ated with its varied uses. MALARIA ERADICATION IN THE 1950S Although malaria has plagued mankind throughout history, 3 it was not until the Eighth World Health Assembly held in Mexico City in May 1955 that health offi- cials from around the world agreed that a malaria eradication program was feasible and should be initiated by WHO. 4 Previous successful control efforts in many parts of the world, especially Eu- rope, the United States, and Ven- ezuela, demonstrated that eradi- cation by residual spraying of insecticides was feasible. 5 A 1952 New York Times article described a fall in the overall worldwide death rate and attributed the “spread of the use of DDT” as one of the major contributing fac- tors. 6 Although DDT resistance by some mosquitoes was ob- served even then, its use, along with that of other candidate in- secticides, was considered an es- sential aspect of an eradication The use of DDT to control ma- laria has been a contentious practice for decades. This controversy centers on con- cerns over the ecological harm caused by DDT relative to the gains in public health from its use to prevent ma- laria. Given the World Health Organization’s recent policy decisions concerning the use of DDT to control malaria, it is worth reviewing the histori- cal context of DDT use. Ecological concerns fo- cused on evidence that DDT ingestion by predatory birds resulted in eggs with shells so thin they were crushed by adult birds. In addition, DDT spraying to control malaria al- legedly resulted in cats being poisoned in some areas, which led to increased rodent populations and, in turn, the parachuting of cats into the highlands of the island of Bor- neo to kill the rodents, a story that influenced the decision to ban DDT spraying. I focus on this story with the intention of grounding the current debate on lessons from the past. (Am J Public Health. 2008;98: 1940–1948. doi:10.2105/ AJPH.2007.122523) PARACHUTING CATS AND CRUSHED EGGS The Controversy Over the Use of DDT to Control Malaria