Case Counts by County

CountyDead birds
Alameda1
Alpine-
Amador-
Butte-
Calaveras-
Colusa-
Contra Costa-
Del Norte-
El Dorado-
Fresno-
Glenn-
Humboldt-
Imperial-
Inyo-
Kern-
Kings-
Lake-
Lassen-
Los Angeles-
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada-
Orange-
Placer-
Plumas-
Riverside1
Sacramento-
San Benito-
San Bernardino-
San Diego22
San Francisco-
San Joaquin-
San Luis Obispo-
San Mateo2
Santa Barbara-
Santa Clara10
Santa Cruz-
Shasta-
Sierra-
Siskiyou-
Solano-
Sonoma2
Stanislaus1
Sutter-
Tehama-
Trinity-
Tulare-
Tuolumne-
Ventura-
Yolo-
Yuba-
Total39

WNV Activity by County
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2015 | 2014 | 2013
2012 | 2011 | 2010
2009 | 2008 | 2007

Press Releases

CALIFORNIA DEPARTMENT OF PUBLIC HEALTH ANNOUNCES FIRST DEATH FROM WEST NILE VIRUS IN 2008

Aug 25, 2008

NUMBER: PH08-46
FOR RELEASE: IMMEDIATE
CONTACT: Suanne Buggy or Lea Brooks
http://www.cdph.ca.gov        
(916) 440-7259

SACRAMENTO - Dr. Mark Horton, director of the California Department of Public Health (CDPH), announced today that West Nile virus (WNV) has claimed the life of an elderly woman in Orange County. She is the first death this year in California from complications associated with the virus.

"This unfortunate death reminds us that we must take precautions to protect ourselves and our families from mosquito bites," Horton said. "Californians should use insect repellent and eliminate all sources of standing water that can support mosquito breeding."

To date in 2008, WNV activity has been detected in 38 of California's 58 counties. In addition to the death, 96 people have become ill with WNV infections in 13 counties. WNV also has been detected in 1,295 dead birds, 1,101 mosquito samples, five horses, 109 sentinel chickens and nine squirrels.

Last year at this time, WNV activity had been detected in 48 counties and 148 people had been confirmed with WNV infections, including nine deaths.

WNV is transmitted to humans and animals through a mosquito bite. Mosquitoes become infected when they feed on infected birds.

Most individuals who are infected with WNV will not experience any illness. However, individuals 50 years of age and older have a higher chance of getting sick and are more likely to develop serious symptoms when infected with WNV. Recent data also indicate that those with diabetes and/or hypertension are at greatest risk for serious illness.

The most effective ways for individuals to prevent exposure to mosquito bites and WNV are:

  • Apply insect repellent containing DEET, picaradin or oil of lemon eucalyptus, according to label instructions.
  • Ensure doors and windows have tight-fitting screens. Repair or replace screens that have tears or holes.
  • Eliminate all sources of standing water that can support mosquito breeding.
  • Wear clothing that reduces the risk of skin exposure and avoid spending time outside at dusk and dawn when mosquitoes are most active.
Most individuals who are infected with WNV will not experience any illness. Individuals 50 years of age and older have a higher chance of getting sick and are more likely to develop serious symptoms when infected with WNV. Recent data also indicate that those with diabetes and/or hypertension are at greatest risk for serious illness.

California's WNV Web site - http://www.westnile.ca.gov - includes the latest information on WNV activity in the state. In order to help identify WNV activity, Californians are encouraged to report all dead birds and dead tree squirrels on the Web site or by calling toll-free 1-877-WNV-BIRD (968-2473).

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Compared to previous year and previous five-year average to date

As of May 22, 2015201520145Y AVG
Counties1096
Human cases000
Dead birds39199
Mosquito samples2573
Sentinel chickens010
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2014 YTD activity -

WNV Reports

Weekly Report

05.22 Arbovirus Bulletin #12
05.22 2015 YTD WNV Activity Map
05.15 Arbovirus Bulletin #11

Humans

04.02 2003-2014 WNV Case Summary
03.09 2014 Human WNV Incidence Report
08.12 2013 Human WNV Incidence Report

Dead Birds

05.22Positive Species for 2015
05.22Positive Counts by City/County for 2015
05.22Reported, Tested, Positive 2015

Mosquitoes

05.22 AMOR - EVS Week 19
05.22 AMOR - GRAVID Week 19
05.22 AMOR - NJLT Week 19
- view report archives -