West Nile Virus

PYRETHROIDS : Sumithrin (Anvil) and Resmethrin (Scourge)

What is West Nile Virus

West Nile virus (WNV) is a mosquito-borne disease that can infect humans, birds, horses and other mammals. In most humans, WNV infection can cause a mild flu-like illness, or may cause no symptoms at all. However in some cases, particularly among the elderly, it can cause severe neurological diseases such as encephalitis or meningitis. West Nile virus first appeared in North America in New York City in 1999. Since then, the virus has spread across the continental United States.

How is West Nile virus spread?

West Nile virus is predominantly spread to humans by the bite of an infected mosquito.

What are pyrethroids?

Pyrethroids are a group of synthetic pesticides used to control adult mosquitoes. They are similar to thenatural pesticide pyrethrum (pyrethrins) produced by chrysanthemum flowers. Pyrethroids are effective against adult mosquitoes including the species most commonly associated with West Nile virus. The two pesticides that contain pyrethroids that may be used by the City are Anvil (sumithrin) and Scourge (resmethrin). Both are approved by the New York State Department of Environmental Conservation (DEC) and the U.S. Environmental Protection Agency (EPA) for the control of adult mosquitoes in urban residential environments. Humans (and other mammals) have the ability to break down pyrethroids and easily remove them from their bodies. Insects have a decreased ability to break down pyrethroids, which results in greater toxicity to insects. To further increase its effectiveness against insects, pyrethroid-based pesticides commonly contain Piperonyl Butoxide (PBO). Both Anvil and Scourge contain PBO.

When will Anvil or Scourge be used?

New York City may spray pesticides to target adult mosquitoes if there is a risk to human health from West Nile virus. The City' is hopeful that with an early and aggressive campaign against mosquito breeding areas the need for spraying of mosquitoes will be reduced.

Where and how will Anvil or Scourge be used?

Spraying by ground (e.g., from trucks) or by air may occur in targeted areas in which the virus has been found. Aerial spraying of larger areas may be necessary depending on the results of human, mosquito, and bird monitoring. The pesticides are applied by licensed applicators following DEC and EPA guidelines. Spraying of these pesticides occurs between dusk and dawn.

What health risks are posed to people and pets from pesticides for adult mosquitoes?

In the amounts used, risks to people and pets are relatively low. However, some people may be more sensitive to pesticides and may want to reduce their chance of exposure by following the suggestions below.

Will the public be notified in advance about spraying activities?

Residents can learn about spraying schedules through public service announcements, the media, the City's website , or by calling 311, the City's Information Line. DOHMH will provide notification at least 24 hours prior to a spray event.

If the City sprays pesticides in an area where I am, what should I do during the spraying?

If pesticide spraying occurs, DOHMH recommends that all individuals take the following precautions to avoid direct exposure to pesticides and to reduce the risk of reactions:

• • Whenever possible, stay indoors during spraying.
• • Some individuals are sensitive to pesticides. Persons with asthma or other respiratory conditions are especially encouraged to stay inside during spraying since there is a possibility that spraying could worsen these conditions.
• • Air conditioners may remain on. But if you wish to reduce the possibility of indoor exposure to the pesticides, turn fans and air conditioners off or set the air conditioner vent to the closed position, or choose the recirculate function.
• • Remove children's toys, outdoor equipment and clothes from outside areas. If toys are left outside, wash them with soap and water before using again.
• • Wash skin and clothing exposed to pesticides with soap and water.
• • Always wash your produce thoroughly with water before cooking or eating.

Anyone experiencing adverse reactions to pesticides should seek medical care or call the NYC Poison Control Center at (212) POISONS (764-7667).

Are pyrethroids safe for the environment?

Pyrethroids break down quickly in sunlight and readily bind to soils. Because of this, they are not expected to contaminate groundwater. Pyrethroids are toxic to bees, fish, and other aquatic life forms and will not be applied to bodies of water.

Can I use pyrethroids around my home?

Products containing pyrethroids are widely available for home use for controlling insects on houseplants and in gardens. Pyrethroids can only be applied for mosquito control by persons who are certified or licensed.

For more information on West Nile virus, call or visit nyc.gov/health/wnv.