Case Counts by County

CountyDead birds
Alameda96
Alpine-
Amador-
Butte22
Calaveras-
Colusa4
Contra Costa44
Del Norte-
El Dorado7
Fresno9
Glenn4
Humboldt2
Imperial-
Inyo-
Kern3
Kings3
Lake18
Lassen-
Los Angeles99
Madera5
Marin6
Mariposa-
Mendocino-
Merced8
Modoc-
Mono-
Monterey-
Napa12
Nevada-
Orange427
Placer40
Plumas-
Riverside1
Sacramento294
San Benito-
San Bernardino17
San Diego34
San Francisco-
San Joaquin53
San Luis Obispo-
San Mateo19
Santa Barbara2
Santa Clara924
Santa Cruz1
Shasta6
Sierra-
Siskiyou-
Solano33
Sonoma37
Stanislaus47
Sutter19
Tehama-
Trinity-
Tulare40
Tuolumne-
Ventura7
Yolo71
Yuba16
Total2430

WNV Activity by County
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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 Nov 21, 2014201420135Y AVG
Counties404440
Human cases752356226
Dead birds24301246897
Mosquito samples333825271963
Sentinel chickens440484425
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2013 YTD activity -

WNV Reports

Weekly Report

11.21 Arbovirus Bulletin #40
11.21 2014 YTD WNV Activity Map
11.18 2014 US Arboviral Activity Update

Humans

11.17 2014 Human WNV Incidence Report
11.17 2003-2014 WNV Case Summary
08.12 2013 Human WNV Incidence Report

Dead Birds

11.21Reported, Tested, Positive 2014
11.21Positive Counts by City/County for 2014
11.21Positive Species for 2014

Mosquitoes

11.07 AMOR - EVS Week 44
11.07 AMOR - GRAVID Week 44
11.07 AMOR - NJLT Week 44
- view report archives -