23 December 2002
Malaria With DDT
The world is losing the war against malaria. Once considered near
eradication, malaria today kills more than a million people a year
in Africa alone. One reason is that wealthy nations have limited
the use of one of the best weapons, a pesticide that once saved
hundreds of millions of lives.
most Americans, DDT is a symbol of the perils of playing God with
nature. DDT accumulates in animals that eat insects, traveling up
the food chain and weakening the eggshells of birds of prey. It
was banned in the United States in 1972.
is one of 12 persistent organic pollutants that an international
treaty had scheduled for a global ban. But at the urging of medical
specialists, the United Nations in 2000 rightly exempted DDT for
use in malaria, saying that it should be banned only when a safe
substitute is found. But there are still too many obstacles preventing
nations that need it from using DDT when appropriate.
malaria control relies mainly on insecticide-treated bed nets and
drugs, most of which have lost effectiveness as malaria grows resistant.
DDT, which is sprayed on the inside walls of houses twice a year,
is used in only about 24 countries. Wealthy nations that banned
DDT at home will not pay for its use elsewhere. But the poorest
nations depend on such donations. America used DDT to eradicate
malaria, as did southern Europe and India.
is hardly risk-free. It poisoned the environment because farmers
sprayed it on crops, a use properly banned today. But very little
DDT is needed to spray houses twice a year. The evidence about DDT's
effects on humans is inconclusive. The uncertainties must be weighed
against a demonstrated effectiveness in fighting a disease that
now kills 1 in 20 African children. DDT also costs one-quarter the
price of the alternative, pyrethroids.