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

Human data is updated every Tuesday 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.
- View Printable Map -

Total Counties with
WNV in 2014: 36

Alameda, Butte, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Humboldt, Kern, Kings, Lake, Los Angeles, Madera, Marin, Merced, Napa, Orange, Placer, Riverside, Sacramento, San Bernardino, San Diego, San Joaquin, San Mateo, Santa Clara, Santa Cruz, Shasta, Solano, Sonoma, Stanislaus, Sutter, Tehama, Tulare, Ventura, Yolo, and Yuba.

CDPH Reports First Human West Nile Virus Fatalities This Summer
SACRAMENTO - The first two deaths this summer due to West Nile virus infection have been confirmed by the California Department of Public Health (CDPH) it was announced today by Dr. Ron Chapman, CDPH Director and state public health officer. The first was a senior citizen from Sacramento County. The second was an adult from Shasta County.
- view news and press release archives -

NOTE:

human cases

YTD: 93 Counties: 18
There were 36 new WNV human cases reported in California this week from the following counties: Butte (4), Colusa (1), Fresno (4), Glenn (1), Los Angeles (4), Orange (12), San Bernardino (1), Santa Clara (3), Stanislaus (5), and Yuba (1). These are the first WNV human cases from Colusa, Glenn, San Bernardino, Santa Clara, and Yuba counties this year.

4 WNV human fatalities from Sacramento (1), Shasta (1), and Stanislaus (2) counties have been confirmed this year.

93 human cases from 18 counties have tested positive for WNV in 2014.

 

dead birds

YTD: 1,480 Counties: 33
There were 70 new WNV positive dead birds reported in California this week from the following counties: Alameda (3), Orange (18), Sacramento (4), San Mateo (1), Santa Clara (43), and Yolo (1).

1,480 dead birds from 33 counties have tested positive for WNV in 2014.

 

mosquito samples

YTD: 2,041 Counties: 29
There were 420 new WNV positive mosquito samples reported in California last week from the following counties: Alameda (4), Butte (6), Contra Costa (2), Fresno (20), Kern (11), Kings (41), Lake (22), Los Angeles (24), Madera (7), Merced (3), Orange (28), Placer (26), Riverside (14), Sacramento (63), San Bernardino (15), San Joaquin (14), San Mateo (2), Santa Clara (4), Shasta (7), Solano (1), Sonoma (2), Stanislaus (17), Sutter (9), Tulare (49), Yolo (26), and Yuba (3).

2,041 mosquito samples from 29 counties have tested positive for WNV in 2014.

 

sentinel chickens

YTD: 129 Counties: 17
There were 23 new WNV positive sentinel chickens reported in California last week from the following counties: Butte (1), Lake (1), Los Angeles (6), Merced (1), Riverside (3), Sacramento (4), San Bernardino (5), Sutter (1), and Yolo (1). These are the first WNV positive sentinel chickens from Riverside, Sacramento, and Yolo counties this year.

129 sentinel chickens from 17 counties have tested positive for WNV in 2014.

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.

2003-2013 WNV Activity Summary

Element 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 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) 4,004 (145)
Horses 12 540 456 58 28 32 18 19 15 22 13 1,202
Dead birds 96 3,232 3,046 1,446 1,396 2,569 515 416 688 1,644 1,251 16,299
Mosquito samples 32 1,136 1,242 832 1,007 2,003 1,063 1,305 2,087 2849 2,528 16,084
Sentinel chickens 70 809 1,053 640 510 585 443 281 391 540 485 5,807
Squirrels - 49 48 32 26 32 10 24 24 23 8 276
1 There were 20 imported human cases. 2 There were 3 imported horse cases.

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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 -