In the last days of September 1943, as the U.S. Army advanced to the rescue of Italian partisans -- some as young as nine -- battling the Germans in the streets of Naples, the enraged Nazis, in a criminal act of revenge against their erstwhile allies, deployed sappers to systematically destroy the city's aqueducts, reservoirs, and sewer system. This done, the supermen, pausing only to burn irreplaceable libraries, including hundreds of thousands of volumes and artifacts at the University of Naples -- where Thomas Aquinas once taught -- showed their youthful Neapolitan opponents their backs, and on October 1, to the delirious cheers of the Naples populace, Allied forces entered the town in triumph.
But a city of over a million people had been left without sanitation, and within weeks, as the Germans had intended, epidemics broke out. By November, thousands of Neapolitans were infected with typhus, with one in four of those contracting it dying of the lice-transmitted disease.[3] The dead were so numerous that, as in the dark time of the Black Death, bodies were put out into the street by the hundreds to be hauled away by carts. Alarmed, General Eisenhower contacted Washington and made a desperate plea for help to contain the disaster.
Fortunately, the brass had a new secret weapon ready just in time to deal with the emergency. It was called DDT,[4] a pesticide of un­prece­dented effectiveness. First synthesized by a graduate student in 1874, DDT went unnoticed until its potential application as an insecticide was discovered by chemist Paul H. Müller while working for the Swiss company Geigy during the late 1930s. Acquainted with Müller's work, Victor Froelicher, Geigy's New York representative, disclosed it to the American military's Office of Scientific Research and Development (OSRD) in October 1942. Examining Müller's data, the OSRD's experts immediately realized its importance. On Guadalcanal, and elsewhere in the South Pacific, the Marines were losing more men to malaria than they were to the Japanese, with the entire 1st Marine Division rendered unfit for combat by the insect-borne disease. Without delay, first Geigy's Cincinnati factory and then the giant DuPont chemical company were given contracts to produce the new pesticide in quantity.[5]
By January 1, 1944, the first shipments of what would eventually amount to sixty tons of DDT reached Italy. Stations were set up in the palazzos of Naples, and as the people walked by in lines, military police officers with spray guns dusted them with DDT. Other spray teams prowled the town, dusting public buildings and shelters. The effects were little short of miraculous. Within days, the city's vast population of typhus-transmitting lice was virtually exterminated; by month's end, the epidemic was over.[6]

January 1944. The U.S. Army uses DDT to end the typhus epidemic in Naples.The retreating Germans, however, did not give up so easily on the use of insects as vectors of death. As the Allied forces advanced north from Naples toward Rome, they neared the Pontine Marshes, which for thousands of years had been rendered nearly uninhabitable by their enormous infestation of virulently malarial mosquitoes. In his most noteworthy accomplishment before the war, Mussolini had drained these marshes, making them potentially suitable for human settlement. The Germans demolished Mussolini's dikes, quickly transforming the area back into the mosquito-infested malarial hellhole it had been for millennia. This promised to be very effective. In the brief Sicilian campaign of early summer 1943, malaria had struck 22,000 Allied troops -- a greater casualty toll than that inflicted by the Axis forces themselves.[7] The malarial losses inflicted by the deadly Pontine Marshes were poised to be far worse.
But the Nazis had not reckoned on DDT. In coordination with their ground forces, the Americans deployed airborne crop dusters, as well as truck dusters and infantry DDT spray teams. Success was total. The Pontine mosquitoes were wiped out. With negligible losses to malaria, the GIs pushed on to Rome, liberating the Eternal City in the early morning of June 5.[8]
From now on, "DDT marches with the troops," declared the Allied high command.[9] The order could not have come at a better time. As British and American forces advanced in Europe, they encountered millions of victims of Nazi oppression -- civilians under occupation, slave laborers, prisoners of war, concentration camp inmates -- dying in droves from insect-borne diseases. But with the armies of liberation came squads spraying DDT, and with it life for millions otherwise doomed to destruction. The same story was repeated in the Philippines, Burma, China, and elsewhere in the Asia-Pacific theater. Never before in history had a single chemical saved so many lives in such a short amount of time.
A Civilian SuccessIn recognition for his role in this public health miracle, Paul Müller was given the Nobel Prize for Medicine in 1948. Presenting the award, the Nobel Committee said: "DDT has been used in large quantities in the evacuation of concentration camps, of prisoners and deportees. Without any doubt, the material has already preserved the life and health of hundreds of thousands."[10]
With the coming of peace, DDT became available to civilian public health agencies around the world. They had good reason to put it to use immediately, since over 80 percent of all infectious diseases afflicting humans are carried by insects or other small arthropods.[11] These scourges, which have killed billions of people, include bubonic plague, yellow fever, typhus, dengue, Chagas disease, African sleeping sickness, elephantiasis, trypanosomiasis, viral encephalitis, leishmaniasis, filariasis, and, most deadly of all, malaria. Insects have also caused or contributed to mass death by starvation or malnutrition, by consuming up to 40 percent of the food crop and destroying much of the livestock in many developing countries.
One of the first countries to benefit from the use of DDT for civilian purposes was the United States. In the years immediately preceding World War II, between one and six million Americans, mostly drawn from the rural South, contracted malaria annually. In 1946, the U.S. Public Health Service initiated a campaign to wipe out malaria through the application of DDT to the interior walls of homes. The results were dramatic. In the first half of 1952, there were only two confirmed cases of malaria contracted within the United States.[12]
Other countries were quick to take note of the American success, and those that could afford it swiftly put DDT into action. In Europe, malaria was virtually eradicated by the mid-1950s. South African cases of malaria quickly dropped by 80 percent; Ceylon (now Sri Lanka) reduced its malaria incidence from 2.8 million in 1946 to 17 in 1963; and India cut its malaria death rate almost to zero. In 1955, with financial backing from the United States, the U.N. World Health Organization launched a global campaign to use DDT to eradicate malaria. Implemented successfully across large areas of the developing world, this effort soon cut malaria rates in numerous countries in Latin America and Asia by 99 percent or better. Even for Africa, hope that the age-old scourge would be brought to an end appeared to be in sight.[13]
But events took another turn with the appearance of Rachel Carson's book Silent Spring.