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WORLD HEALTH ORGANIZATION USES CONTROVERSIAL INSECTICIDE TO COMBAT MALARIA
PBS
September 18, 2006
The World Health Organization (WHO) has fully endorsed the use of one of the most
powerful insecticides ever developed, DDT, to fight malaria, a deadly disease carried by
mosquitoes.
For the past 30 years the WHO, the United Nation's health agency, has rejected the use of
DDT because it causes genetic problems in animals and has been linked to cancer in
humans.
However, it is one of the most effective chemicals when it comes to killing the Anopheles
mosquito, which carries the deadly malaria parasite.
Malaria kills more than one million people each year and 90 percent of those deaths
occur in sub-Saharan Africa.
Using DDT in a controlled manner
According to the WHO's plan, DDT will be used in a controlled manner, sprayed on the
walls and roofs of houses only, instead of mass spraying outdoors.
This technique, called indoor residual spraying, is tentatively endorsed by environment
groups like the Environmental Defense, the Sierra Club and the Endangered Wildlife
Trust.
"Reluctantly, we do support it," said Ed Hopkins, the director of the Sierra Club's
environmental quality program.
"Malaria kills millions of people and when there are no other alternatives to indoor use of
DDT, and where that use will be well-monitored and controlled, we support it."
Indoor spraying can reduce malaria transmission by up to 90 percent, the WHO claims.
During a press conference on September 15, Dr. Arata Kochi, director of the WHO
malaria department, called DDT "one of the best tools" available to fight the disease.
A group called Beyond Pesticides opposed the new policy, saying that DDT “causes
greater long-term problems than those that are being addressed in the short-term.”
The malaria epidemic
Malaria is one of the most common and deadly diseases in the world. It is preventable
and treatable, but can be deadly if left untreated.
Humans contract malaria from the bite of a malaria-infected mosquito. Parasites travel
from the saliva in the mosquito’s mouth into the human blood.
The parasites then travel to the person’s liver, where they grow and multiply. The
parasites also enter the bloodstream and invade red blood cells, where they multiply
again.
Eventually, the red blood cells burst, releasing toxins that cause symptoms such as fever
and lack of energy. Malaria may also damage the nervous system and vital organs such as
liver and kidney.
There are at least 300 million serious cases of malaria each year worldwide, resulting in
more than one million deaths. It is especially deadly to women and children. The disease
causes one in every five child deaths in Africa.
Stopping the spread
African nations located south of the Sahara Desert face a series of problems that make the
malaria epidemic hard to control. The Anopheles mosquitoes flourish in the region's
climate, and countries are economically unable to pay for all the medication needed.
There are some cheap malaria drugs available, but when the same drug is used in a
widespread manner to combat a disease, strains of the disease develop resistance to that
drug.
As supplying medications that will work becomes more difficult, prevention becomes
critical.
Prevention includes mosquito netting placed around beds and draining stagnant water,
where the mosquitoes live and lay their eggs.
But these efforts alone have not been enough, which is why the WHO has turned to DDT
now.
''Indoor spraying is like providing a huge mosquito net over an entire household for
around-the-clock protection,'' said U.S. Senator Tom Coburn, R-Okla., a doctor who
attended the press conference.
The rise and fall of DDT
DDT was discovered as a powerful insecticide in the late 1930s. At the time, it was
celebrated as a miracle insecticide.
The chemical was used in mass quantities in the United States, sprayed in homes and
over fields and marshes, to combat malaria.
The spraying eliminated the disease in the United States by 1949 and farmers continued
to use DDT to protect their crops from insects.
However, in 1962, biologist Rachel Carson wrote a book called “Silent Spring,” which
helped set off the environmental movement in America by documenting how mass
spraying of DDT entered the food chain, causing cancer and genetic damage and
threatening to wipe out some bird species, including bald eagles.
The effects on humans are still being debated, but in 1969, the National Cancer Institute
released findings suggesting that DDT could cause cancer. The United States banned
DDT in 1972, and many other countries followed the example.
In 2004 the global treaty on Persistent Organic Pollutants banned DDT worldwide,
except for use in controlling diseases like malaria.
Senator Tom Coburn's activity on the Subcommittee on Federal Financial Management, Government Information, and International Security
340 Dirksen Senate Office Building Washington, DC 20510
Phone: 202-224-2254 Fax: 202-228-3796
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