Case Counts by County

CountyDead birds
Alameda54
Alpine-
Amador-
Butte11
Calaveras-
Colusa4
Contra Costa25
Del Norte-
El Dorado1
Fresno8
Glenn4
Humboldt2
Imperial-
Inyo-
Kern3
Kings2
Lake12
Lassen-
Los Angeles21
Madera4
Marin3
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa8
Nevada-
Orange156
Placer19
Plumas-
Riverside-
Sacramento223
San Benito-
San Bernardino8
San Diego4
San Francisco-
San Joaquin36
San Luis Obispo-
San Mateo8
Santa Barbara-
Santa Clara682
Santa Cruz1
Shasta2
Sierra-
Siskiyou-
Solano31
Sonoma12
Stanislaus27
Sutter19
Tehama-
Trinity-
Tulare38
Tuolumne-
Ventura2
Yolo40
Yuba10
Total1480

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

Special - Resources

West Nile Virus Information for Physicians

Aug 3, 2012

West Nile virus (WNV) has been detected in many regions of the state. Physicians should:


  • Be aware if WNV is active in their area
  • Look for symptoms of WNV
  • Test for WNV because testing:

    • differentiates WNV from other conditions (enterovirus, other arboviral diseases) and thus may prompt a change in treatment regime
    • results offer anticipatory guidance--both WNV neuroinvasive disease and WN fever patients can have lingering symptoms and knowing the underlying etiology is helpful for the patient and family members
    • helps mosquito control and public health agencies institute proper control measures to reduce the risk of further cases in the event of a positive result

  • Contact their local public health department for details on sample submission and testing


For additional information, please see these resources:

Locate Your Local Mosquito and Vector Control Agency
Search by Zip Code

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

As of Aug 20, 2014201420135Y AVG
Counties363932
Human cases935933
Dead birds1480834508
Mosquito samples20411349994
Sentinel chickens129176107
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2013 YTD activity -

WNV Reports

Weekly Report

08.20 2014 YTD WNV Activity Map
08.19 2014 US Arboviral Activity Update
08.15 Arbovirus Bulletin #26

Humans

08.18 2014 Human WNV Incidence Report
08.18 2003-2014 WNV Case Summary
08.12 2013 Human WNV Incidence Report

Dead Birds

08.20Reported, Tested, Positive 2014
08.20Positive Counts by City/County for 2014
08.20Positive Species for 2014

Mosquitoes

08.15 AMOR - EVS Week 32
08.15 AMOR - GRAVID Week 32
08.15 AMOR - NJLT Week 32

Horses

12.16 2010 Equine WNV Result Map
12.16 2010 Confirmed Equine Cases Report
05.26 2009 Equine WNV Result Map
- view report archives -