Occasionally I state views in this column with which readers disagree. Some of them have been about evolution, alternative medicine, wind turbines and atomic energy. I honor those who disagree with me about these issues. One recent column, however, drew responses about which I feel very differently.
My column on June 3 honored Rachel Carson, whose "Silent Spring" remains the most important book of the environmental movement, a highly literate argument against the uncontrolled use of pesticides in American agriculture.
Most attacks on her book and Carson personally were easily answered. She was deeply informed; she relied on analyses by dozens of reputable scientists; her data were carefully checked. Unsuccessful on these fronts, Carson's critics focused on her arguments against the pesticide DDT, claiming that removing this mosquito control made her responsible for many malaria deaths.
A single quote (interestingly it was repeated in two of the communications I received) will indicate the response that bothers me: "Rachel Carson is responsible for more deaths than Pol Pot." Sadly, that statement represents the carefully mounted and continuing attack on Carson.
DDT played an extremely important disease-controlling role in World War II, but consider the following:
* Its supporters credit DDT with eliminating malaria in this country but that disease was already largely gone here by 1939 when Hermann Mueller discovered that the chemical was lethal to insects.
* An international campaign led by Fred Soper to eliminate malaria through use of DDT that indeed saved thousands of lives had largely run out of steam by the early 1960s when "Silent Spring" was published. Mosquitoes were building up resistance and geographical factors particularly in African countries, made spraying extremely difficult. Between 1960 and 1989 deaths from malaria actually decreased when treatment shifted from insecticides to medicine.
* Carson never did call for banning DDT and other pesticides in "Silent Spring." She wrote, "It is not my contention that chemical insecticides must never be used. I contend that we have allowed these chemicals to be used with little or no advance investigation of their effect on soil, water, wildlife and man himself."
* The 1972 Environmental Protection Agency ban of DDT in America was instituted 10 years after "Silent Spring" was published and eight years after the author's death from cancer. Although Carson's influence was evident, the act cites substantial scientific evidence of DDT's adverse effects on wildlife and increased insect resistance.
* The focus of "Silent Spring" was on the indiscriminative use of insecticides for agricultural purposes, not on its use as a public health measure. Carson critics have made much of the World Health Organization's 2006 approval of DDT, but that approval is "under strict control and only for indoor residual spraying," thus exactly the kind of use Carson supported.
There are serious public health problems underlying disease vector control. Here's the scenario: "Bad bugs" are identified -- insects that carry diseases like malaria or even the diseases themselves. Scientists develop chemicals that kill the bugs -- vectors or viruses -- but then two problems arise.
First, the chemicals rarely kill all the bad bugs. Those that remain pass resistance to their offspring. The immunity of subsequent generations builds and ever stronger chemicals in ever greater quantities are required. Second, the chemicals kill good bugs as well -- beneficial insects that prey on the bad bugs -- or they injure physiological responses to the viruses -- like blood cells. In nature, there are always fewer predators than prey so problems with the bad bugs are increased.
This chemical scenario does not just apply to malaria. We see it playing out today with the developing scourge of the superbug MRSA (Methicillin-resistant Staphylococcus aureus) that is tougher than most of our strongest antibiotics.
These are very serious problems, but sadly they are clouded by political and profit agendas. I agree with Ezra Klein's analysis of the attack on Rachel Carson: "The demonization of Carson has nothing to do with malaria death -- the Competitive Enterprise Institute, which is supporting the effort, certainly isn't agitating for increased foreign aid and public health projects. It's about discrediting environmentalists, and environmentalism, more generally."
I am especially saddened by these industry-supported right wing attacks because of my high regard for the hummingbird photography of Crawford Greenewalt, former DuPont president. I cannot believe he would have sponsored such malicious and unwarranted attacks.