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  • West Nile Virus

    Reduce your exposure to mosquitoes.

    In August 2018, Washington State Department of Health detected West Nile virus in mosquito samples from the Gog-le-hi-te Wetlands on the Tacoma tide flats. Samples taken later that season tested negative for the virus.

    The next summer we partnered with the Department of Health to increase West Nile virus testing. We took mosquito samples from even more sites around Pierce County, to better detect risk of West Nile virus.

    All samples taken that year—including those from the Gog-le-hi-te Wetlands—tested negative for the virus. Even so, West Nile virus still poses a risk to our community. Read more below to learn how to protect yourself from mosquito bites.

    West Nile Virus - What you should know


    West Nile Virus FAQs

    West Nile virus is almost always spread to people by the bite of an infected mosquito. Mosquitoes become infected after feeding on birds that carry the virus. There is no evidence that West Nile virus can be spread by direct contact with infected people or animals.

    Symptoms of West Nile virus include headache, fever, muscle and joint aches, swollen lymph nodes and a rash. Symptoms usually develop 2 to 14 days after an infected mosquito bites you. Those with more severe symptoms—like severe headache, stiff neck or confusion—should get medical attention.

    Health officials have not seen any cases of West Nile virus in Pierce County among people, birds or horses. West Nile activity typically shows up early to mid-August. People should take steps to control mosquito populations and prevent exposure to bites.

    It only takes one bite to acquire the virus from an infected mosquito, and West Nile virus can pose a health threat to anyone exposed. But less than 1 percent of people infected with the virus will develop severe illness. Some are at higher risk of severe disease, including people 60 years old or older, those with compromised immune systems or underlying medical conditions.

    Drain, dress and repel.

    You can take simple steps to avoid mosquito bites and reduce mosquito breeding sites around your home.

    • Drain and routinely empty anything that holds water, like gutters, pet bowls, tires, bird baths at least twice a week. Keep water moving in ornamental ponds by recirculating water or by installing a fountain.
    • Dress in long-sleeved shirts and long pants, especially at dawn and dusk when mosquitoes are most active.
    • If outdoors, use mosquito repellent where mosquitoes are active.

    Use properly fitted door and window screens and stay indoors around dawn and dusk.

    The most effective mosquito repellents contain the active ingredient of DEET (N, N-diethyl-m-toluamide), picaridin, IR3535, oil of lemon eucalyptus, PMD the synthesized version of oil of lemon eucalyptus, or 2-undecanone. These active ingredients typically offer long-lasting protection against mosquito bites. Repellents come in lotions, creams, gels, sprays, and towelettes.

    You must use mosquito repellents properly. Read and follow instructions on the label. Don’t over use repellents.

    West Nile virus infects a variety of wild birds. Of those birds infected, crows, jays, ravens, magpies, and raptors, such as hawks and owls tend to become sick and die. Increasing numbers of dead birds may be an indication of West Nile virus in your community.

    Washington State Department of Health tests birds request by local health departments and tracks where tested birds are found. The agency, however, no longer tracks public reporting of dead birds. In recent years, monitoring of mosquitoes has proven to be a more reliable indication of current West Nile virus activity.

    Dispose of the dead bird safely. Don’t handle it with your bare hands. Use gloves or an inverted plastic bag to place the bird in a garbage bag, and dispose in your outdoor garbage can.

    You can report dead birds to Department of Fish & Wildlife, Report Observations of Dead Wildlife. They investigate the cause of death involving large wild bird die-offs, including suspected diseases such as West Nile virus.

    West Nile virus can cause serious illness in horses, mules, and donkeys. Though most horses that become infected will not get sick, about 1 in 3 horses infected will die. To protect your horse, ask your veterinarian about the West Nile virus vaccine. West Nile virus can infect dogs and cats, but it is rare.


    Washington State Department of Health