Wetlands: A Public Health Hazard

By Dr. Jane Orient

In 1985, a new species immigrated into the United States, hitching a ride to Houston on some used tires from Japan: the Asian tiger mosquito, Aedes albopictus. Since then, it has made itself at home in 20 Southern, border, and Midwestern states.

This mosquito likes to live near people, in tire dumps, tin cans, flowerpots, birdbaths, or anything else that contains a small amount of water. It is aggressive and feeds on many different hosts. It grows viruses well and spreads them effectively. In Asia, it is a major vector for dengue (“bone break”) fever, painful but usually nonfatal encephalitis that occurs in the U.S. The most worrisome form is called Eastern equine encephalitis. This virus is fatal in 80% of its victims and destroys the brain in half of the survivors (Arizona Republic, June 6, 1992).

Although the tiger mosquito is not endangered (and entitled to protection), mosquitoes’ breed in protected habitat: wetlands.

The definition of a wetland is controversial. A 1989 manual issued by the Environmental Protection Agency (EPA) and other agencies defined it as any area that was wet for seven continuous days per year and had soil saturated to within sic to 18 inches of the surface. The burden of proof was on the landowner to prove that the land was not a wetland in order to obtain a development permit from the Army Corps. A more restrictive definition has been proposed by Vice President Quayle’s Council on Economic Competitiveness and the Domestic Policy Council’s Task Force on Wetlands: the land would have to be covered with water for at least 15 straight days or saturated to the surface for 21 consecutive days during the growing season and would have to meet more stringent requirements concerning the type of vegetation present. It would also place the responsibility on the federal agencies to prove that the land is a wetland and hence subject to regulation (Issues in Science and Technology VIII:35-41, Summer, 1992).

Environmentalists oppose the new definition, claiming that “major wetland destruction” could easily result. Their concern is for migratory birds and the flora and fauna that thrive in wetlands.

Public health officials have a different concern. Their definition of a functional wetland is a “place where water stands long enough to produce two successive broods of mosquitoes.”

Officials responsible for protecting the public health, however, are not even listed among the “interested groups” opposed to regulatory “protection” (agriculture, real estate, construction, and oil and gas production).

Scientists deplore the “neglect of 600 million patients” worldwide due to inadequate research for developing drugs against tropical diseases (Science 256:1135, May 22, 1992). They also call for investing greater effort in vaccine development, which has to date been remarkably ineffective against parasitic diseases such as malaria (Science 257:36-38, July 3, 1992). ] But “attack against the mosquito vector has always offered the only hope for eradication of the parasite” (ibid)

Attack against the vector means draining swamps and using pesticides. Both methods are increasingly constrained.

At the Tenth Annual Meeting of Doctors for Disaster Preparedness, held in Costa Mesa, CA, July 11, 1992, William Hazeltine, Ph.D., described the problems he faced as manager of the Butte County Mosquito Abatement District. In California, the best pesticides have become unavailable. A chemical previously used to treat pastures is now allowed by the State of California only for use against household pests. But pasture mosquitoes and jackrabbits are an important part of the endemic encephalitis virus life cycle. An alternative compound, pyrethrin, derived from the Chrysanthemum flower, costs $300 per pound and is in such short supply that it may be impossible to treat all the densely populated urban areas that are at risk.

Concern about the carcinogenic potential of minuscule residual concentrations of pesticides is only part of the problem, according to Hazeltine. The pesticide also has to have been proved effective to the regulators’ satisfaction. That is why the use of diesel oil is not permitted (even though no one doubts its efficacy), unless some approved ingredient is added to it.

Hazeltine does not believe that the nation’s fish, shellfish, migratory birds, aquifers, shorelines, and recreational opportunities face dire due to efforts to control vectors of human disease. He cites numbers compiled by the Soil Conservation Service of the USDA, that showed the average loss of privately owned wetlands in the Pacific States to be about 8,000 acres per year between 1982 and 1987. “This does not square with the catastrophic loss numbers being used to achieve a political objective.”

Hazeltine did not comment on DDT, believing that battle was irretrievably lost. Dr. Edward Teller asked whether it would be an exaggeration to say that the ban on DDT had cost 10 to 20 million human lives.

“I believe that to be an underestimate,” Hazeltine replied.

Dr. Jane Orient is the Vice President of Physicians for Civil Defense headquartered in Tucson, Arizona.

Editors Note: Estimates on the deaths caused by the unnecessary banning of DDT run as high as 8 million per year.
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