News Article
From New York Times
HEADLINE:
DDT, Target of Global Ban, Finds Defenders in Experts on Malaria
BYLINE: By SHERYL GAY STOLBERG
DATELINE: August 29, 1999, Sunday, Late Edition - Final - WASHINGTON, Aug. 28.
SECTION: Section 1; Page 1; Column 2; Foreign Desk
It has been 27 years since the United States banned the pesticide DDT, and the
payoff is undeniable. The peregrine falcon, once pushed to the brink of
extinction, came off the endangered species list this month, and the bald eagle
may soon follow. Brown pelicans are flourishing in Florida. On the shores of
Long Island, the ospreys are back.
Now the United Nations is drafting a treaty that may lead to a worldwide ban on
DDT. But the negotiations, set to resume in Geneva next month, are drawing
opposition from an unlikely quarter: public health professionals, who say
DDT is
necessary to stop the spread of malaria, a disease that kills as many as 2.7
million people each year, mostly children in undeveloped countries.
"A child dies of malaria every 12 seconds," said Dyann F. Wirth, a malaria
expert at the Harvard School of Public Health and president of the American
Society of Tropical Medicine and Hygiene. "That could go up dramatically if we
lose this important control tool."
Dr. Wirth is among more than 370 medical researchers in 57 countries who are
urging that the treaty allow DDT to be sprayed in small quantities on the
interior walls of homes, where it acts as a repellent to the disease-carrying
insects. The scientists argue that if the pesticide, which is cheap and
effective, must be eliminated, it should be phased out gradually, and only if
Western countries conduct research on the more expensive alternatives and help
pay for them.
Some type of public health exception is likely, said Jim Willis, director of
chemicals for the United Nations Environmental Program, which is sponsoring the
talks. But the specifics are engendering intense acrimony between the public
health experts and environmentalists, and have created some friction in the
Federal Government, as it tries to formulate its policy for the negotiations.
"This poses an unusual dilemma," said a State Department official involved in
the talks. "Usually the dynamic is protection versus economics. There, it is
very easy for one side to paint the other as the black hat. But here there is a
peculiar tradeoff between health and the environment."
Most countries no longer use DDT for agricultural purposes (or do not admit to
it if they do), but experts estimate that 23 nations still use it for malaria
control. The biggest users are China and India. Mexico has pledged to stop
spraying DDT by 2007. And the World Bank has lent India $200 million to help
devise alternatives to DDT.
The DDT dilemma stems from a United Nations plan to eliminate, or greatly
reduce, the use of 12 toxic chemicals classified as persistent organic
pollutants. The group -- "the dirty dozen" to environmentalists -- consists of
eight pesticides, including DDT, as well as chemical byproducts and industrial
chemicals. All accumulate in the food chain and can travel thousands of miles
through air, water and bird migration, causing lasting contamination.
In her 1962 book "Silent Spring," Rachel Carson, a marine biologist, chronicled
DDT's poisonous effects, showing, for example, how it killed the robins
that ate
the earthworms that dined on the leaves of Dutch elm trees that had been
sprayed
with the insecticide. The public outcry was tremendous; the book led to the
establishment of the Environmental Protection Agency in 1970 and the United
States ban on DDT in 1972.
The treaty negotiations on the group of pollutants began in 1998 and are
scheduled to conclude by the end of next year. The Geneva meeting, which runs
from Sept. 6 to 11, is the third of five scheduled sessions, but the first to
examine each chemical in detail. Mr. Willis of the United Nations predicted "a
rather thorough discussion of the DDT issue."
Among advocacy groups hoping to influence the talks, that discussion is already
under way, and it is fraught with competing studies and statistics. Experts are
arguing about everything from whether DDT is harmful to human health (the
evidence is inconclusive) to whether the recent rise in malaria rates in Mexico
results from cutbacks in spraying, or from last year's hurricanes, which
provided fertile breeding grounds for mosquitoes. (The answer is probably
both.)
"Positions have hardened," said Dr. Gerald T. Keusch, director of the Fogarty
International Center, the branch of the National Institutes of Health
devoted to
promoting scientific research overseas. "In the heat it has not been
possible to
step back and look at the light."
On one side is the nonprofit World Wildlife Fund and Physicians for Social
Responsibility, a doctors' group concerned with environmental health. They
argue
that even small amounts of DDT sprayed inside homes are harmful to the
environment and cite studies suggesting that the pesticide turns up in the
breast milk of nursing mothers and has other "subtle effects on human health."
Taking its cue from Mexico, the wildlife fund is pressing for a ban on DDT by
2007. But the idea of a specific date is extremely contentious, and the State
Department official said the United States would not ask for one.
On the other side are two scientists' groups, the tropical medicine
society, and
the Malaria Foundation International, a nonprofit organization dedicated to
promoting research. Several months ago, at the behest, curiously enough, of a
Vancouver environmental lawyer and cell biologist, Amir Attaran, the foundation
posted a letter about the negotiations on its Web site, arguing that "setting a
firm deadline to ban DDT places an unethical burden on the world's poorest
countries."
As of Thursday, 371 scientists, including 3 Nobel laureates, had signed. As the
group's founder, Dr. Mary Galinski, a molecular biologist at Emory
University in
Atlanta, explained: "We don't want a knee-jerk reaction to ban DDT."
The debate is occurring as malaria is making a deadly comeback, re-emerging in
regions where it was once under control and killing many more people than
it did
decades ago, at least partly because of a reduction in DDT use. The World
Health
Organization estimates that there are 300 million to 500 million new cases of
the disease each year, and last year started a project called Roll Back Malaria
to combat it.
There are drugs to treat malaria, but some patients cannot afford them and drug
resistance is an increasing problem. So the best means of prevention is to keep
mosquitoes from biting people. At least one expert, Dr. Donald R. Roberts
of the
Uniformed Services University of the Health Sciences in Bethesda, Md., argues
that "DDT is the best insecticide we have today for controlling malaria."
In the late 1970's, Dr. Roberts, a medical zoologist, traveled to Brazil to
conduct experiments in malaria control. He built two houses and sprayed the
inside of one with DDT. Hundreds of mosquitoes entered the unsprayed house, he
said. None entered the sprayed house. Since then, Dr. Roberts has become an
ardent defender of DDT. "We have got to stop pressuring countries to stop using
DDT," he said. "It is immoral."
Others, including Dr. Galinski, say they have no problem eliminating the
pesticide, so long as alternatives are in place. But that is a frightening
thought to Dr. Wen Kilama, a Tanzanian entomologist who in June presided
over an
expert panel, convened by the World Health Organization, to debate the
future of
the pesticide in malaria prevention.
Because mosquitoes develop resistance to pesticides, Dr. Kilama says that
getting rid of DDT would be a mistake. "The mosquitoes are very complex and one
should not rely on one measure alone, particularly one type of insecticide," he
said in a telephone interview last week. "It's like when you fight, you have a
pocketful of arrows and now you have only one arrow left."
Tanzania no longer uses DDT; the country cannot afford it, Dr. Kilama said. But
with the economy improving, he added, "I can see a lot of hope coming up" that
Government-sponsored spraying might resume. In the meantime, some Tanzanians
sleep under nets soaked in pyrethroids, another chemical. But the nets cost $4
to $5 apiece, too high a sum for many villagers, and Dr. Kilama said they work
only by "mass effect," which means entire neighborhoods must use them.
Further south, in Botswana, health officials have also abandoned DDT, but for a
different reason. Only three countries -- China, India and Mexico -- still
manufacture the pesticide, and Thandie Phindela, a malaria control officer in
Botswana's Ministry of Health, said the country could not get a reliable supply
this year. "The environmentalists are trying to put pressure on the use of
DDT,"
she said. "We had to resort to pyrethroids."
But pyrethroids are more expensive. According to Kathleen Walker, an
entomologist with the E.P.A., the cost of treating one house with DDT ranges
from $1.60 to $8.50, compared with $4.20 to $24 for pyrethroids. In the
end, she
said, some countries may have to abandon house spraying altogether and begin
research on other, cheaper alternatives.
That is the World Wildlife Fund's view: its contaminants expert, Richard
Liroff,
urges "more creative thinking about moving away from DDT." He points to an
experiment in India, where gambusia -- a larvae-eating fish -- were
deposited in
bodies of water where mosquitoes breed. But Dr. Kilama, of Tanzania, said such
steps are not practical in a country where a hippopotamus footprint after a
heavy rain can create an instant breeding ground.
As the debate continues, the World Health Organization is drafting its own plan
to help countries cut back on DDT. But the organization has no idea how
much the
effort will cost; the price tag will vary from nation to nation. As to who will
pay, said Jenny Pronczuk, a chemical safety expert, "Well, that's a problem."
GRAPHIC: Photos: DDT kills birds, but it also repels mosquitoes that spread
malaria. (Sinclair Stammers/Photo Researchers); Health officials say DDT is
needed to fight malaria's threat to poor children. In Kisii, Kenya, a father
brought his child for treatment. (Reuters)(pg. 8)
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