DDT may offer answer to West Nile's spread

Friday, September 27, 2002

So far this year, about 2,000 Americans have contracted West Nile virus, mostly from the bites of the common evening mosquito. Nearly 100 deaths due to West Nile virus have been confirmed in the United States. However, the total number of West Nile cases and deaths may be far greater. Many Americans who get West Nile recover quickly and are never tested for the virus. Some deaths resulting from the virus are attributed to other causes.

While public-health officials are concerned about the West Nile virus, they also must put the virus in perspective with other deadly illnesses and disease. One comparison that is being made these days as the West Nile death toll rises is with another mosquito-borne killer: malaria.

About 1,000 new cases of malaria are reported in the United States each year. Almost all of these cases are the result of travel to other parts of the world where malaria is endemic. In this country, treatment is generally successful unless other complications arise from the malaria parasite. In the United States, malaria-related deaths are rare.

That's not the case around the world, however. Each year, some 300 million to 500 million new cases of malaria are reported in countries where there is little prevention or treatment, and more than 1 million people die of malaria each year. In Africa, malaria is the No. 2 overall cause of death (HIV is No. 1 as of last year) and the No. 1 killer of children.

By some estimates, malaria killed more people worldwide than any other disease prior to the introduction in 1939 of dicholorodiphenyltrichloroethane, better known as DDT. The effectiveness of DDT was widely hailed, but its use wasn't limited to disease-carrying insects. It also was commonly used as a general agricultural pesticide in the United States, leaving large concentrations of the chemical compound in fields and in surface water supplies. In the 1960s, DDT was blamed for the near extermination of several bird species, including the bald eagle, ospreys and brown pelicans.

After saving millions of lives around the world, the use of DDT was banned in the United States in 1972 because of environmental concerns.

As with many environmental issues, there are strong arguments to support that decision, but with the continuing scourge of malaria there also are arguments for allowing public-health officials to use DDT to save lives. And now, those arguments are being used as a way to eliminate the West Nile virus in the United States.

There is a point with every deadly illness at which human life outweighs certain other risks. Countries such as Ecuador, for example, have increased their use of DDT since the early 1990s to combat malaria. Ecuador has effectively reduced malaria within its borders -- the largest such reduction in the world.

DDT is the most affordable and most effective pesticide in dealing with mosquitoes. Properly used within the limited scope of eradicating the West Nile virus, DDT could put an end to the growing fear of the outdoors as more and more Americans contract the virus.

With the onset of winter weather, concerns about West Nile virus will soon abate, only to return next spring. In the meantime, the idea of using DDT should be carefully considered.

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