Home Brentwood West Nile Virus Detected in Brentwood, Discovery Bay and Knightsen

West Nile Virus Detected in Brentwood, Discovery Bay and Knightsen

by ECT

CONCORD, CALIFORNIA – – The Contra Costa Mosquito & Vector Control District confirmed today that one dead bird each from Danville and Discovery Bay, a horse from Brentwood, and four chickens from the Knightsen area tested positive for West Nile virus.


“We monitor virus in insects and animals because it provides an indication that people are at risk of becoming infected,” said the District’s Scientific Programs Manager Steve Schutz, Ph.D. “Everyone should take all the recommended precautions to avoid mosquito bites.  While the majority of people who become infected with West Nile virus do not experience symptoms, some develop West Nile fever or encephalitis, which can lead to paralysis, long-term disability or even death.”


District personnel are conducting extra surveillance and mosquito control in the areas where the virus activity was found.


The District urges the public to report dead birds to the state hotline: 1-877-968-2473. Birds are often the first sign of disease transmission. Even if the birds are not tested, the reports alone yield crucial information to protect public health.


Residents can reduce their risk of contracting mosquito-borne diseases by following these guidelines:

  • Dump or drain standing water. Mosquitoes can’t begin their lives without water.
  • Defend yourself – use repellents containing DEET, Picaridin, or Oil of Lemon Eucalyptus.
  • Avoid being outdoors when mosquitoes are present, typically dawn and dusk.
  • Maintain neglected swimming pools. Just one can produce more than 1 million mosquitoes and affect people up to five miles away.
  • Report dead birds to the state hotline: 1-877-968-2473 or by visiting the California Department of Public Health’s website. All reports are crucial.

Since 2005, 56 people in Contra Costa County have been diagnosed with West Nile virus. In 2006, two people died from the disease. For a current list of West Nile virus activity this year, visit this page on the District’s website.  For human case information, please contact Contra Costa Health Services at 888-959-9911.

Mosquito Samples: 2

nDate ReportedCityCross StreetsSpecies
17/26/17DIscovery BayPoint of TImber Rd. x Poe Dr.Culex pipiens
28/2/17ByronByron Hwy x Rankin Rd.Culex tarsalis

Dead Birds: 5

nDate ReportedCityCross StreetsSpecies
17/26/17Walnut CreekYgnacio Valley Rd. x Wiget Ln.American Crow
27/26/17Walnut CreekYgnacio Valley Rd. x Wiget Ln.American Crow
38/1/2017Walnut CreekYgnacio Valley Rd. x Wiget Ln.American Crow
48/3/2017DanvilleBrookside Dr. x Greenbrook Dr.American Crow
58/8/2017Discovery BayHighway 4 x Discovery Bay Blvd.Western Scrub Jay

Sentinel Chicken Flocks: 1

Note: Chickens do not die from West Nile virus. They develop antibodies to the virus which is detected in their blood.

#/10Date BleedArea

Horses: 1

Contra Costa Mosquito & Vector Control District, an independent special district and public health agency, is located at 155 Mason Circle in Concord. Call the District to report mosquito problems at (925) 771-6195 or visit the office between 8:00 a.m. and 4:30 p.m. to get FREE mosquitofish for ornamental ponds, horse troughs or neglected swimming pools.

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