Case Counts by County

CountyDead birds
Alameda12
Alpine-
Amador-
Butte33
Calaveras-
Colusa3
Contra Costa4
Del Norte-
El Dorado2
Fresno1
Glenn4
Humboldt2
Imperial-
Inyo-
Kern1
Kings3
Lake5
Lassen-
Los Angeles12
Madera1
Marin3
Mariposa-
Mendocino-
Merced1
Modoc-
Mono-
Monterey-
Napa5
Nevada9
Orange25
Placer8
Plumas-
Riverside39
Sacramento61
San Benito-
San Bernardino4
San Diego107
San Francisco-
San Joaquin11
San Luis Obispo-
San Mateo8
Santa Barbara-
Santa Clara83
Santa Cruz-
Shasta10
Sierra-
Siskiyou-
Solano7
Sonoma4
Stanislaus13
Sutter16
Tehama-
Trinity2
Tulare22
Tuolumne-
Ventura6
Yolo48
Yuba6
Total581

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

Human data is updated every Friday by 4pm. Dead bird data is updated every Wednesday and Friday by 4pm. Mosquito and sentinel chicken data are updated on Fridays by 4pm.

Due to different reporting schedules, case totals on this website may not always be consistent with those reported by local health departments.

Interactive Map

View the interactive map courtesy of http://maps.calsurv.org
- View Printable Map -

Total Counties with
WNV in 2015: 40

New counties highlighted in red.
Alameda, Butte, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Humboldt, Kern, Kings, Lake, Los Angeles, Madera, Marin, Mendocino, Merced, Napa, Nevada, Orange, Placer, Riverside, Sacramento, San Bernardino, San Diego, San Joaquin, San Mateo, Santa Barbara, Santa Clara, Shasta, Siskiyou, Solano, Sonoma, Stanislaus, Sutter, Tehama, Trinity, Tulare, Ventura, Yolo, and Yuba.

CDPH Confirms First Human West Nile Virus Death of 2015
SACRAMENTO - California Department of Public Health (CDPH) Director and State Health Officer Dr. Karen Smith today announced the first confirmed death in California due to West Nile virus (WNV). The deceased person was a senior citizen in Nevada County.
- view news and press release archives -

human cases

YTD: 83 Counties: 19
There were 26 new WNV human cases reported in California this week from the following counties: Butte (6), Glenn (4), Kern (1), Riverside (1), San Bernardino (1), San Joaquin (1), Siskiyou (1), Stanislaus (3), Sutter (2), Tehama (1), Yolo (1), and Yuba (4). These are the first WNV human cases from San Joaquin, Stanislaus, Sutter, Yolo, and Yuba counties this year. This is the first indication of WNV from Siskiyou County this year.

Two WNV-related fatalities have been reported in to CDPH from San Bernardino (1) and Nevada (1).

83 human cases from 19 counties have tested positive for WNV in 2015.

 

dead birds

YTD: 581 Counties: 36
There were 78 new WNV positive dead birds reported in California this week from the following counties: Alameda (1), Butte (3), Contra Costa (1), Lake (2), Los Angeles (8), Napa (2), Nevada (1), Orange (3), Placer (3), Riverside (5), Sacramento (6), San Diego (20), San Joaquin (1), San Mateo (1), Santa Clara (11), Shasta (2), Stanislaus (3), and Yolo (5).

581 dead birds from 36 counties have tested positive for WNV in 2015.

 

mosquito samples

YTD: 2,073 Counties: 29
There were 305 new WNV positive mosquito samples reported in California this week from the following counties: Butte (2), Fresno (14), Kern (10), Kings (26), Lake (4), Los Angeles (32), Madera (8), Orange (87), Placer (1), Riverside (8), Sacramento (16), San Bernardino (25), San Joaquin (17), Shasta (3), Stanislaus (11), Sutter (1), Tulare (28), and Yolo (12).

2,073 mosquito samples from 29 counties have tested positive for WNV in 2015.

 

sentinel chickens

YTD: 174 Counties: 20
There were 24 new WNV positive sentinel chickens reported in California this week from the following counties: Los Angeles (4), Placer (3), Riverside (3), San Bernardino (7), Santa Clara (3), Solano (3), and Yolo (1). These are the first WNV positive sentinel chickens from Riverside and Santa Clara counties this year.

174 sentinel chickens from 20 counties have tested positive for WNV in 2015.

Be a West Nile Watcher

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 Aug 28, 2015201520145Y AVG
Counties403632
Human cases8312554
Dead birds5811573751
Mosquito samples207324841702
Sentinel chickens174184151
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2014 YTD activity -

WNV Reports

Weekly Report

08.28 Arbovirus Bulletin #26
08.28 2015 YTD WNV Activity Map
08.25 2015 US Arboviral Activity Update

Humans

08.28 2015 Human WNV Incidence Report
08.28 2003-2015 WNV Case Summary
03.09 2014 Human WNV Incidence Report

Dead Birds

08.28Positive Species for 2015
08.28Positive Counts by City/County for 2015
08.28Reported, Tested, Positive 2015

Mosquitoes

08.28 AMOR - EVS Week 33
08.28 AMOR - GRAVID Week 33
08.28 AMOR - NJLT Week 33
- view report archives -