Although DDT is better known for its health side effects, its repellent effects have played an important role in modern history.
What Is DDT?
An insecticide developed in the late 1800's and first utilized during World War II, DDT was used to control insect-borne diseases like malaria and typhus. By 1945, farmers were able to readily purchase the pesticide as an agricultural insecticide.
Moderately toxic, it kills insects by opening sodium ion channels in the brain. This causes neurons to spontaneously fire, which in turn leads to spasms and death. It is hydrophobia and strongly absorbed by soils, remaining in the ground for as long as 30 years after its initial usage.
Successful Repellent
By 1955, the World Health Organization was advocating for increased DDT use in its attempted to eradicate malaria once and for all. Although their program was largely a success in the far east, the Caribbean, the Balkans, northern Africa, Australia and the South Pacific, it became clear that resistance was being built up by insect populations due to its widespread use.
Concerns Mount
Due to the fact that DDT was being used to rid crops of insects en masse, a public health concern soon arose with worries about the insecticide's toxicity. Tests were undertaken that served to prove that the bald eagle population in the United States was suffering, their eggs becoming brittle because of DDT ingestion.
The Bans
1968 saw the first banning of DDT in Hungary, followed shortly by Norway and Sweden in 1970, the U.S. in 1972, and the United Kingdom in 1984. As a vector control, however, DDT's use is still permitted in many countries.
Toxicity
Ingesting DDT in any quantity will place the toxin in the organism's body fat deposits for an unknown period of time. The following organisms have suffered the effects of DDT to date:
1. Crayfish
2. Daphnids
3. Sea Shrimp
4. Cats
5. Amphibians
6. Bald eagles
7. Brown pelicans
8. Peregrine falcons
9. Osprey
10. Waterfowl
11. Song birds
12. Humans
The negative effects observed in human beings include premature birth, early pregnancy loss, low birth weight, low semen quality, and a variety of bodily cancers.
DDT vs. Malaria
Presently, DDT is primarily used as a means to eradicate mosquito populations that cause malaria, one of the world's largest public health challenges. The World Health Organization advocates for house-spraying with DDT in areas of the world where malaria is prevalent, mostly in Africa.
As a result of the adverse effects of the insecticide that are continuing to be determine, however, spraying with alternative pesticides is done whenever possible. Other possible means to control the spread of malaria without DDT include the use of bed nets, mesh screens, mosquito-eating fish, and the constant draining of standing water sources.
Tags: Health Organization, public health, World Health, World Health Organization