Contact: , American Bird Conservancy, 202/234-7181 ext. 207

Spraying pesticides to combat West Nile virus, the wrong response

Spraying pesticides in urban and suburban areas does little to reduce the spread of West Nile Virus, is extremely harmful to birds and may also harm the humans it is intended to protect.

Some of the chemicals being used to combat West Nile have direct, toxic effects on birds and other wildlife, while others are highly toxic to non-target and beneficial insects, such as butterflies, bees and dragonflies, and to most aquatic life. Rampant spraying of pesticides greatly reduces the numbers of insects available as food to resident birds and the millions of migratory warblers, thrushes and shorebirds that stop in areas that have been sprayed. Run-off and aerial drift of sprayed pesticides contaminates ecosystems distant from the original site of pesticide application making dangers less predictable and controllable.

A significant body of research shows that mosquito insecticides are also harmful to human health. Pyrethroids, said by mosquito control officials to be harmless to humans are in fact suspected endocrine disrupters, and have also been shown to cause chromosome abnormalities. In laboratory studies, many of the organophosphate insecticides being used cause neurological disorders, immune dysfunction and cancer.

West Nile Virus has had a far greater impact on birds than humans in North America with sixty bird species (including Merlins, Great Horned Owls, Catbirds, warblers, gulls, swans and at least one Bald Eagle), amounting to thousands of individual birds, testing positive to date. By contrast, there have been only eight human deaths from West Nile in the U.S. in two years.

Scientific evidence suggests that mosquito spraying actually enhances infection rates in the birds that reservoir the virus by directly compromising the avian immune response thus making them more susceptible to infection. Additionally, mosquitoes that survive insecticide exposure may be affected in ways that make them more efficient transmitters of the infectious virus. American Bird Conservancy suggests measures for containing West Nile Virus should mirror preventive measures currently taken by public health and mosquito abatement officials for St. Louis Encephalitis - a similar virus, as outlined by the Centers for Disease Control. These measures generally do not entail the spraying of adult mosquitoes in residential or suburban areas. Instead, controlling mosquitoes at the larval stage using less toxic methods is advocated and remains the most effective and least environmentally harmful methodology available.

"The response to West Nile is a typical example of how pesticides are used to control perceived risk…risks they often end up compounding," said Kelley Tucker, Director of American Bird Conservancy’s Pesticides and Birds Campaign. "As the outbreak of West Nile Virus has shown, birds are important sentinels of environmental health. We can’t afford to ignore them".