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-
Riverside-
Sacramento-
San Benito-
San Bernardino-
San Diego4
San Francisco-
San Joaquin-
San Luis Obispo-
San Mateo1
Santa Barbara-
Santa Clara3
Santa Cruz-
Shasta-
Sierra-
Siskiyou-
Solano-
Sonoma-
Stanislaus-
Sutter-
Tehama-
Trinity-
Tulare-
Tuolumne-
Ventura-
Yolo-
Yuba-
Total9

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

Data on this website is updated every Friday by 4pm.

Due to different reporting schedules, case totals on this website may not always be consistent with those reported by local health departments.
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Total Counties with
WNV in 2015: 8

New counties highlighted in red.
Alameda, Los Angeles, Riverside, San Diego, San Mateo, Santa Barbara, Santa Clara, and Tulare.

California Sets Record for West Nile Virus Activity
SACRAMENTO - It was a record-breaking year for West Nile virus activity in 2014 California Department of Public Health (CDPH) Director and State Health Officer Dr. Karen Smith announced today.
- view news and press release archives -

Click for 2014 WNV Activity

human cases

YTD: 0 Counties: 0
No cases of human WNV illness have been reported positive for WNV in 2015.
 

dead birds

YTD: 9 Counties: 4
There was 1 new WNV positive dead bird reported in California last week from San Diego County.

9 dead birds from 4 counties have tested positive for WNV in 2015.

 

mosquito samples

YTD: 5 Counties: 4
There have been 2 new WNV positive mosquito samples reported in California last week from Riverside (1) and Tulare (1) counties. This is the first indication of WNV from Tulare County this year.

5 mosquito samples from 4 counties have tested positive for WNV in 2015.

 

sentinel chickens

YTD: 0 Counties: 0
No sentinel chickens have tested positive for WNV in 2015.

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Help us track down the West Nile Virus by reporting all dead birds. You can submit an online report by clicking on the button on the right.

2003-2014 WNV Activity Summary

Element 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Total
Human cases (fatal) 31 (0) 779 (29) 880 (19) 278 (7) 380 (21) 445 (15) 112 (4) 111 (6) 158 (9) 479 (20) 379 (15) 801 (31) 4,805 (176)
Horses 12 540 456 58 28 32 18 19 15 22 13 03 1,202
Dead birds 96 3,232 3,046 1,446 1,396 2,569 515 416 688 1,644 1,251 2,442 18,741
Mosquito samples 32 1,136 1,242 832 1,007 2,003 1,063 1,305 2,087 2849 2,528 3,340 19,424
Sentinel chickens 70 809 1,053 640 510 585 443 281 391 540 485 443 6,250
Squirrels - 49 48 32 26 32 10 24 24 23 03 03 276
1 There were 20 imported human cases. 2 There were 3 imported horse cases. 3 No longer monitored.

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

As of May 01, 2015201520145Y AVG
Counties874
Human cases041
Dead birds9145
Mosquito samples541
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

05.01 Arbovirus Bulletin #9
05.01 2015 YTD WNV Activity Map
04.24 Arbovirus Bulletin #8

Humans

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

Dead Birds

05.01Positive Species for 2015
05.01Positive Counts by City/County for 2015
05.01Reported, Tested, Positive 2015

Mosquitoes

05.01 AMOR - EVS Week 16
05.01 AMOR - GRAVID Week 16
05.01 AMOR - NJLT Week 16
- view report archives -