Case Counts by County

CountyDead birds
Alameda85
Alpine-
Amador-
Butte19
Calaveras-
Colusa4
Contra Costa38
Del Norte-
El Dorado3
Fresno9
Glenn4
Humboldt2
Imperial-
Inyo-
Kern3
Kings3
Lake16
Lassen-
Los Angeles57
Madera5
Marin3
Mariposa-
Mendocino-
Merced1
Modoc-
Mono-
Monterey-
Napa12
Nevada-
Orange291
Placer38
Plumas-
Riverside1
Sacramento271
San Benito-
San Bernardino12
San Diego7
San Francisco-
San Joaquin45
San Luis Obispo-
San Mateo14
Santa Barbara-
Santa Clara836
Santa Cruz1
Shasta5
Sierra-
Siskiyou-
Solano32
Sonoma19
Stanislaus39
Sutter19
Tehama-
Trinity-
Tulare40
Tuolumne-
Ventura4
Yolo63
Yuba16
Total2017

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 Sep 17, 2014201420135Y AVG
Counties384137
Human cases31115095
Dead birds20171067727
Mosquito samples285321731643
Sentinel chickens302330253
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2013 YTD activity -

WNV Reports

Weekly Report

09.17 2014 YTD WNV Activity Map
09.16 2014 US Arboviral Activity Update
09.12 Arbovirus Bulletin #30

Humans

09.15 2014 Human WNV Incidence Report
09.15 2003-2014 WNV Case Summary
08.12 2013 Human WNV Incidence Report

Dead Birds

09.17Reported, Tested, Positive 2014
09.17Positive Counts by City/County for 2014
09.17Positive Species for 2014

Mosquitoes

09.12 AMOR - EVS Week 36
09.12 AMOR - GRAVID Week 36
09.12 AMOR - NJLT Week 36
- view report archives -