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DDT is an abbreviation for a compound known as dichlorodiphenyltrichloroethane.
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- How Is DDT Used? DDT is used for residual
treatment of walls in dwellings in areas where malaria transmission
occurs. DDT has been used in malaria control programmes
since the late 1940s, often with great success. DDT is particularly
useful when used in combination with improvements in housing
counditions, such as screening of windows and doors. DDT
is less costly than more modern chemicals used for mosquito
control, such as the pyrethroids. Thus, in certain cases
DDT is affordable while other compounds are not. Remember
that malaria occurs in countries that are very often highly
strapped for money.
- How Dangerous is DDT to People? Very
few (probably no) human deaths or illnesses have been conclusively
linked to proper usage of DDT. On the other hand, proper
usage of DDT has prevented many illnesses and deaths that
would have occurred as a result of malaria.
- Are There Regions Where DDT No Longer Works?Anopheles
mosquitoes are physiologically resistant to DDT in some
regions, and thus DDT is not effective in these areas. Currrent
insecticide resistance test data should be used when planning
malaria control efforts. Much resistance test data is 15-30
years old, and current resistance test data should be gatbered.
- Are There Regions where DDT is Still Effective?In
some regions. the vectors of malaria are still susceptible
to DDT, and the compound remains effective in blocking malaria
transmission. An example is control of Anopheles funestus
in South
Africa.
- How Is DDT Used for Malaria Control?DDT
usage for malaria control involves spraying the walls and
backs of furniture in dwellings. These treatments are aimed
at adult mosquitoes that come into the dwelling to feed
on the occupants. DDT used in this manner also controls
leishmaniasis, a disease that can be deadly or disfiguring
and that occurs in the Indian subcontinent, Asia, and South
America. Robert Desowitz, a noted student of tropical public
health, has written about leishmaniasis and malaria in The
Malaria Capers.
- Is DDT Used Outdoors? There are now highly
effective biological larvicides [Bacillus thuringiensis
israelensis] for larval mosquito control, and outdoor
DDT usage is inappropriate.
- What About the Hazards of DDT? DDT is
hazardous to certain wildlife species and should not be
used outdoors or in natural areas. DDT toxicity to human
beings is low. The appropriate use of DDT is to treat human
dwellings and other buildings where mosquitoes enter to
bite people.
- Is There a Moral Dimension to this Question?
Yes. Certain countries with high morbidity and mortality
rates from malaria have trouble affording high-tech medical
treatments or the latest insecticides. If DDT is effective
for use against vectors in these regions it should be used
to prevent premature death and disability. The preservation
of human life is paramount.
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