Case Counts by County

CountyDead birds
Alameda86
Alpine-
Amador-
Butte20
Calaveras-
Colusa4
Contra Costa38
Del Norte-
El Dorado4
Fresno9
Glenn4
Humboldt2
Imperial-
Inyo-
Kern3
Kings3
Lake18
Lassen-
Los Angeles60
Madera5
Marin3
Mariposa-
Mendocino-
Merced7
Modoc-
Mono-
Monterey-
Napa12
Nevada-
Orange306
Placer38
Plumas-
Riverside1
Sacramento275
San Benito-
San Bernardino13
San Diego7
San Francisco-
San Joaquin47
San Luis Obispo-
San Mateo14
Santa Barbara-
Santa Clara852
Santa Cruz1
Shasta5
Sierra-
Siskiyou-
Solano32
Sonoma20
Stanislaus43
Sutter19
Tehama-
Trinity-
Tulare40
Tuolumne-
Ventura5
Yolo67
Yuba16
Total2079

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: 38

New counties highlighted in red.
Alameda, Butte, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Humboldt, Imperial, Kern, Kings, Lake, Los Angeles, Madera, Marin, Mendocino, 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.

West Nile Virus at Highest Level Ever in Mosquitoes
SACRAMENTO - Dr. Ron Chapman, director of the California Department of Public Health (CDPH) and state health officer, is reminding Californians to remain vigilant against the threat of West Nile virus.
- view news and press release archives -

NOTE:

human cases

YTD: 311 Counties: 28
There were 73 new WNV human cases reported in California last week from the following counties: Colusa (1), Fresno (2), Glenn (2), Los Angeles (20), Mendocino (1), Orange (31), Placer (2), Sacramento (3), San Bernardino (3), San Joaquin (1), Santa Clara (1), Shasta (1), Stanislaus (1), Tehama (1), Tulare (2), and Yolo (1). This is the first WNV human case from Yolo County this year. This is the first indication of WNV from Mendocino County this year.

12 WNV-related fatalities have been reported in to CDPH from in eight local health jurisdictions: Glenn (1), Long Beach City (1), Los Angeles (1), Orange (3), Sacramento (1), Shasta (1), Stanislaus (2), and Sutter (2).

311 human cases from 28 counties have tested positive for WNV in 2014.

 

dead birds

YTD: 2,079 Counties: 35
There were 100 new WNV positive dead birds reported in California last week from the following counties: Alameda (2), Butte (1), Contra Costa (2), El Dorado (1), Kings (1), Lake (3), Los Angeles (3), Merced (6), Orange (28), Sacramento (4), San Bernardino (1), San Joaquin (2), San Mateo (1), Santa Clara (31), Sonoma (3), Stanislaus (4), Tulare (2), Ventura (1), and Yolo (4).

2,079 dead birds from 35 counties have tested positive for WNV in 2014.

 

mosquito samples

YTD: 2,952 Counties: 29
There were 99 new WNV positive mosquito samples reported in California last week from the following counties: Alameda (1), Contra Costa (1), Fresno (5), Kern (4), Los Angeles (30), Orange (26), Placer (1), Riverside (4), Sacramento (7), San Bernardino (4), San Joaquin (4), Santa Clara (1), Stanislaus (7), Sutter (1), Tulare (1), and Yolo (2).

2,952 mosquito samples from 29 counties have tested positive for WNV in 2014.

 

sentinel chickens

YTD: 328 Counties: 21
There were 26 new WNV positive sentinel chickens reported in California last week from the following counties: Alameda (1), Butte (2), Colusa (2), Los Angeles (7), Merced (2), Riverside (2), Shasta (1), Sonoma (1), Sutter (1), Tehama (5), and Yuba (2). This is the first WNV positive sentinel chicken from Alameda County this year.

328 sentinel chickens from 21 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 Sep 19, 2014201420135Y AVG
Counties384137
Human cases31115095
Dead birds20791067727
Mosquito samples295223141749
Sentinel chickens328374301
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2013 YTD activity -

WNV Reports

Weekly Report

09.19 Arbovirus Bulletin #31
09.19 2014 YTD WNV Activity Map
09.16 2014 US Arboviral Activity Update

Humans

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

Dead Birds

09.19Reported, Tested, Positive 2014
09.19Positive Counts by City/County for 2014
09.19Positive Species for 2014

Mosquitoes

09.18 AMOR - EVS Week 37
09.18 AMOR - GRAVID Week 37
09.18 AMOR - NJLT Week 37
- view report archives -