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West Nile / mosquito spraying overview

Human cases, 2005

As of Friday, California tallied 753 reported human cases from 38 counties in 2005. Reported human cases of the disease in regional counties: Sacramento, 165; Stanislaus, 73; San Joaquin, 32; Placer, 32; Butte, 19; Yolo, 12; Sutter, nine; Solano, four; Nevada, four; Tehama, three; Yuba, two; Plumas, one; El Dorado, one.

Where to get information

  • To report a dead bird, call (877) 968-2473
  • Sacramento and Yolo counties: Residents can request mosquitofish, report untreated pools of standing water, get aerial spraying information and sign up for e-mail notification of local insecticide treatments by calling the Sacramento-Yolo Mosquito and Vector Control District at (800) 429-1022 or (916) 685-1022, or at
  • Placer County: Residents can get information and obtain mosquitofish by calling the Placer Mosquito Abatement District at (916) 435-2140.
  • For updates and changes to the ground-spraying schedule, go to or call (916) 435-2140.
  • For other information, call the Placer West Nile virus line at (530) 889-4001 or go to or
  • Butte County: Residents can go to or call (800) 339-2941.
  • Anyone with concerns about the health effects of spraying can call the California Poison Control number at (800) 876-4766.
  • Other Web sites: Centers for Disease Control and Prevention,; state Department of Health Services,
  • Prevention tips

    To reduce the risk of catching West Nile virus, the Sacramento-Yolo Mosquito and Vector Control District recommends:

    • Use an effective mosquito repellent containing ingredients such as DEET, Picaridin or oil of lemon eucalyptus.
  • Repair tears in door and window screens.
  • Drain standing water.
  • Wear long pants and long sleeves outdoors when practical.
  • Avoid being outside at dawn and dusk, when mosquitoes are most active.
  • Virus symptoms

    • About 80 percent of people who get West Nile virus have no symptoms, and 19 percent get flulike symptoms that include fever, aches and fatigue.
    • Fewer than 1 percent of West Nile victims will contract neuroinvasive disease, symptoms of which can include paralysis of the arms or legs, chronic headaches and chronic fatigue.

    What to do in spray zones

    Officials say residents in the spray zone are not at risk and do not need to take precautions for themselves, for pets or for livestock. For those who remain concerned, they're suggesting ways to reduce exposure:

    • Stay inside and keep doors and windows closed between 8 p.m. and midnight. The mist stays in the air up to 90 minutes after release.
    • Turn off air conditioning or ventilation systems during spraying.
    • Bring patio furniture, toys and pets indoors for the evening. Cover items left outside.
    • Remove shoes before coming inside until spraying ends.
    • Wash outdoor furniture and other items people might touch. But don't create pools of water that could become mosquito breeding grounds.
    • Fruits, vegetables and herbs from gardens should be washed but will be safe to eat.
    • Swimming pools do not need to be covered and will be safe for swimming after the applications.
    • For more information, call (800) 429-1022 or check
    • More tips: Insect control can be pesky
    • What's in the pesticide

      The ingredients in EverGreen Crop Protection EC 60-6, the pesticide that is being sprayed:

      • Active ingredients: Pyrethrins (a killing agent extracted from chrysanthemum flowers), 6 percent; piperonyl butoxide (known as PBO, this "synergist" slows an insect's ability to break down pyrethrins; it is classified as a "possible" cancer-causing agent by the U.S. Environmental Protection Agency), 60 percent.
    • Inert (nonactive) ingredients: Glycol ethers (a solvent and inactive byproduct of PBO), less than 1 percent; petroleum distillates (refined kerosene, a solvent used to dissolve the active ingredients), about 5 percent.
    • Remainder: A proprietary mixture designed to dissolve and bind all ingredients together. It includes ionic and anionic surfactants (soap chemicals found in dishwashing soaps and laundry detergents; these enable the solution to be diluted in water or oil) and sorbitan monooleate (an oil emulsifier and stabilizer that allows the product to be mixed with oil for application).
    • Join the discussion

      Post your thoughts on West Nile virus/mosquito spraying forum

      Magpie-count aid sought

      Holly Ernest, a wildlife veterinarian at the University of California, Davis, is coordinating a volunteer network to count magpies to help learn how much West Nile virus is affecting their numbers. Ernest is asking people who walk daily or commute by bicycle to look for and count magpies. To participate, contact

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