NYTimes Op-Ed: Place for DDT for WNV?

August 7, 2003
Is There a Place for DDT?
By HENRY I. MILLER

STANFORD, Calif.-The outbreak of West Nile virus in the United States
is rapidly becoming a significant threat to public health. With the
peak season just beginning, the mosquito-borne virus has been found
in animals (primarily birds and horses) in 38 states, and has caused
103 serious infections and three deaths in humans in 15 states.

Last year, there were more than 4,000 cases and almost 300 deaths. We
may be on the verge of an epidemic, but there is no treatment and a
vaccine is at least a decade away.

Public health officials have recognized the seriousness of the
problem, but too often their response has been tepid and designed to
avoid controversy. The Centers for Disease Control Web site, for
example, advises people to avoid mosquito bites by covering up, using
insect repellent, and staying indoors during peak mosquito hours.
Missing from its list of suggestions, however, is any mention of
insecticides or widespread spraying. Anyone curious about the role of
pesticides in battling mosquitoes and West Nile is directed to a maze
of other Web sites.

In the absence of a vaccine, elimination of the organism that spreads
the West Nile virus - in this case, the mosquito - is the key to
prevention, but fundamental shortcomings in public policy limit the
tools that are available.

In 1972, on the basis of dubious data about toxicity to fish and
migrating birds, the Environmental Protection Agency banned virtually
all uses of the pesticide DDT, an inexpensive and effective pesticide
once widely deployed to kill disease-carrying insects. Allowing
political sentiment to trump science, regulators also cited the
possibility that DDT posed a cancer risk for humans - an assertion
based on studies showing an increased incidence of the illness in
mice that were fed extremely high doses of the pesticide.

Not only did government regulators minimize scientific evidence of
the safety and effectiveness of DDT, they also failed to appreciate
the distinction between its large-scale use in agriculture and more
limited application for controlling carriers of human disease.
Although DDT can be a toxic substance, there is a big difference
between applying large amounts of it in the environment - as American
farmers did before it was banned - and applying it carefully and
sparingly to fight mosquitoes and other disease-carrying insects. A
basic principle of toxicology is that the dose makes the poison.

The regulators who banned DDT also failed to take into consideration
the inadequacy of alternatives. Because it persists after spraying,
DDT works far better than many pesticides now in use, some of which
are toxic to fish and other aquatic organisms. (While its longevity
poses risks, they are minimized with targeted use.) Also, the need to
spray other insecticides repeatedly drives up costs. For example,
budget problems compelled Maryland this summer to turn down requests
for spraying from communities badly infested with mosquitoes.

Given the long-term ineffectiveness of other pesticides, DDT remains
the best alternative to fighting mosquitoes and the West Nile virus.
It's worth recalling that DDT worked before, eradicating malaria from
the United States. It's worth recalling, too, that since DDT was
widely banned, insect-borne diseases like malaria and dengue fever
have been on the rise worldwide. The World Health Organization
estimates that malaria kills about one million people annually, and
that there are 300 million to 500 million new cases each year.

How can we drain the public policy swamp? First, the government
should undertake a re-evaluation of the voluminous data on DDT that
has been compiled since the 1970's. It should also make DDT available
for mosquito control in the United States.

Second, the United States should oppose international strictures on
DDT. This includes retracting American support for the United Nations
Persistent Organic Pollutants Convention, which makes it exceedingly
difficult for developing countries - many of which are plagued by
malaria - to use DDT.

Finally, federal officials should embark on a campaign to educate
local authorities and citizens about the safety and potential
importance of DDT. Right now, most of what people hear is the
reflexively anti-pesticide drumbeat of the environmental movement.

Because DDT has such a bad rap, it will be politically difficult to
resurrect its use. But we should begin the process now. In the
meantime, we'll just slather on the insect repellent, slap, scratch -
and occasionally become infected with a life-threatening but
preventable disease.

Henry I. Miller, a doctor, is a fellow at the Hoover Institution. He
was a Food and Drug Administration official from 1979-1994.

Copyright 2003 The New York Times Company

--
-----------------------------------------------------------------------------------------------------------------
WESTNILEVIRUS-L is an email discussion group for communication and discussion
about West Nile Virus, particularly regarding policy, risk reduction and public
education issues. It is moderated by Dr. Lois Levitan at Cornell University's
Environmental Risk Analysis Program.  Archives are posted at:
http://environmentalrisk.cornell.edu/WNV/WNV-L_ArchiveIndex.html.
To subscribe (or unsubscribe), send an email request with your name and contact
information to <envrisk@cornell.edu>. To receive messages once a day in digest
format,  subscribers can send an email to <listproc@cornell.edu> with message:
"set WESTNILEVIRUS-L mail digest-nomime".
Subscribers are encouraged to post to the group by sending messages to
<envrisk@cornell.edu>.  Please put "WNV Listserv" in the subject line and
send only unformatted text, without attachments.
-----------------------------------------------------------------------------------------------------------------