SILENT SPRING: A NEW LIFE FOR DDT?
Some estimates suggest that DDT has saved millions of human lives since 1945 by preventing diseases such as malaria, bubonic plague, sleeping sickness, and typhus.
Insect resistance to DDT was identified as early as 1955 in Africa, and by 1972 populations of 19 mosquito species worldwide had shown resistance to DDT. A World Health Organization study in 2000 in Vietnam suggested that non-DDT malaria controls were significantly more effective than DDT use.
In light of questions about its persistence, growing resistance in insects, and safety, DDT has fallen out of favor around the world. It is banned in many countries.
However, DDT continues to be used in the fight against malaria in parts of the developing world by being sprayed on the inside walls of houses to repel insects. The World Health Organization (WHO) supports this strategy:
The debate continues.
Advocates suggest that DDT restrictions should be loosened to allow more widespread use against malarial mosquitoes. This case emphasizes that malaria is a demonstrated killer (over 1 million people each year, mostly children) while the health effects of DDT on humans are far less certain. Studies show accumulation of DDT in the liver of personnel spraying DDT (but with no evident health effects) and there is also some evidence linking this type of DDT with increases in breast cancer through exposure before puberty. The reported links between human illness and DDT continue to be subject to dispute.