The following op-ed ignores recent research on human health costs
of DDT, including strong associations between DDT
exposure and pre-term birth, and fertility
impairment of women exposed in the womb. A new
review of this work, just published in a journal from the
Centers for Disease Control, estimates that the increase in infant
mortality caused by DDT may completely offset the benefits of
using DDT for decreasing infant mortality caused by malaria. If
the author and other DDT enthusiasts want to renew the debate
over DDT use in the US and elsewhere, at the very least they should
do so with scientific integrity.
7 August 2003
There A Place For DDT?
By Henry I. Miller
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
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.
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
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.
1972, on the basis of dubious
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
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.
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.
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.
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.
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.
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.
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
I. Miller, a doctor, is a fellow at the Hoover Institution. He was
a Food and Drug Administration official from 1979-1994.