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First Birds Test Positive for West Nile Virus in Santa Clara County


SANTA CLARA COUNTY, CALIF. – The Santa Clara County Vector Control District (SCCVCD) has confirmed that three dead American Crows have tested positive for West Nile Virus (WNV) in the South Bay. The birds were found on May 7 in Monte Sereno (zip 95030), on May 10 in Los Altos (zip 94022), and on May 13 at Bollinger Road and Johnson Avenue in San Jose (zip 95129).

Dead birds act as an early warning system for West Nile Virus. A bird that tests positive for WNV alerts health officials that the virus is present in an area. Transmitted by mosquito bites, WNV causes mild to severe flu-like symptoms such as fever, headache, body ache and, in severe cases, significant neurological symptoms or even death. The elderly and those with compromised immune systems are most susceptible. In 2009, California reported 129 WNV infections, with 112 symptomatic cases and four fatalities.

No human cases or WNV positive mosquitoes have been found in Santa Clara County this year. SCCVCD is continuing to collect adult mosquitoes weekly throughout the county for testing.

The SCCVCD asks Santa Clara County residents to report crows, jays, sparrows, finches, birds of prey or tree squirrels that have been dead for less than 48 hours and do not appear to have died because of an injury. They should contact the State of California WNV hotline at 877-WNV-BIRD (2473) or online at

In light of the heavy rainfall this season, mosquito abatement remains the key to preventing West Nile Virus. Consequently, SCCVCD has stepped up its mosquito surveillance and outreach programs. Residents are asked to eliminate standing water on their properties to help eliminate mosquito breeding sources. A single poorly maintained pool in the back yard can produce millions of mosquitoes.

It is also important for all residents to take the following precautions against mosquito bites:

    • Protect yourself if you are outside when mosquitoes are most active, especially at dawn and the first two hours after sunset.
    • When outdoors, wear long pants and long-sleeved shirts.
    • Apply insect repellant, such as DEET, according to label instructions.
    • Make sure that doors and windows have tight-fitting screens. Repair or replace screens that have tears or holes.
    • Contact the Vector Control District if you are being bothered by mosquitoes or know of a potential mosquito-breeding source.

For assistance on mosquito control and WNV, residents can contact Santa Clara County Vector Control District office by calling (408) 918-4770 / (800) 675-1155 or online at

Media Contact: Noor Tietze 408-210-5773, Russ Parman 408-593-6176, José Colomé 408-210-5774
Posted: May 17, 2010

Positive Detections 2010