Word: ddt
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
...early decades of the 20th century, farmers had few pesticides at their disposal more effective than arsenates to protect their crops from insect depredations. During World War II, German and Allied laboratories produced complex and lethal chemical compounds, including DDT and lindane. Since then new generations of pesticides such as carbamates (Bux Ten, Furadan and Mobam) have proved to be efficient at curbing insects and microscopic pests without producing the strong toxic effects of DDT on the environment. At the same time, however, these new silent killers still pose a potential threat to other forms of life, including human...
Janis fished some sandwich bags from her pack, and Jeff began collecting pieces of eggshell, olive brown flecked with mocha spots, membrane gooey on the white inside. Somebody with a micrometer would check the specimens for thickness. In the days of DDT, the shells thinned dangerously, though not fatally. In the days of acid rain, one worries−without evidence, so far−that the shells might thin again...
...Africa, Sicily and the South Pacific fell victim to the disease. The U.S. Army responded with what has been called "a biological Manhattan Project." It led to development of chloroquine. More effective than quinine, it was hailed as a wonder drug. Wartime research also yielded a wonder pesticide: DDT. It was the potent combination of chloroquine and massive DDT spraying in Asia, South America and Africa (and even in the U.S., where there were pockets of malaria as recently as 1950) that fostered WHO's rosy vision of conquering malaria once...
...1960s, Plasmodium falciparum, the most lethal of the four species of parasite that cause human malaria, showed signs of becoming resistant to chloroquine. Soon there were resistant strains on three continents. About the same time, health officials around the Mediterranean began to find mosquitoes that were immune to DDT. It was a classic illustration of Darwinian evolution: a handful of mosquitoes that were DDT-resistant and a tiny number of parasites that were drug-resistant had survived, multiplied and defeated the best efforts of modern science. Malaria returned with a vengeance. In just four years, the incidence in Sri Lanka...
Malaria research had largely come to a halt during the years that chloroquine and DDT seemed all conquering. But Dr. Ruth Nussenzweig of N.Y.U. continued to pursue a malaria vaccine, a goal many viewed as impossible. The malaria bug presented unique obstacles. The first was the complex life cycle of the Plasmodium parasite, which is in a sense three bugs in one (see diagram): the sporozoite, which enters the human bloodstream when an infected mosquito bites; the merozoite, which invades the red blood cells and causes the disease's chills and fever; and the gametocyte, which, when ingested...