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World
Health Organization Uses Controversial Insecticide to Combat Malaria
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Posted:
09.18.06
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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.
Printer-friendly version: PDF
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 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.
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Using DDT
in a controlled manner |
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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."
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The malaria
epidemic |
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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.
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Stopping
the spread |
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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.
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The rise
and fall of DDT |
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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.
--Compiled
by Talea Miller for NewsHour Extra
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