CA Dept. of Public Health UC Davis Arbovirus Research and Training Mosquito and Vector Control Assoc. of CA

Case Counts by County

CountyDead birds
Alameda5
Alpine-
Amador-
Butte3
Calaveras-
Colusa-
Contra Costa5
Del Norte-
El Dorado-
Fresno3
Glenn-
Humboldt-
Imperial-
Inyo-
Kern-
Kings3
Lake3
Lassen-
Los Angeles50
Madera2
Marin2
Mariposa-
Mendocino-
Merced3
Modoc-
Mono-
Monterey-
Napa-
Nevada-
Orange19
Placer11
Plumas-
Riverside4
Sacramento293
San Benito-
San Bernardino-
San Diego175
San Francisco-
San Joaquin20
San Luis Obispo-
San Mateo9
Santa Barbara-
Santa Clara48
Santa Cruz1
Shasta-
Sierra-
Siskiyou-
Solano1
Sonoma-
Stanislaus6
Sutter6
Tehama-
Trinity-
Tulare1
Tuolumne-
Ventura11
Yolo30
Yuba1
Total715

WNV Activity by County
Printable Version
2016 | 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.

April 17 - 23 is West Nile and Mosquito and Vector Control Awareness Week in California! This week highlights the importance of preventing mosquito bites and protecting Californians from mosquito-borne diseases. Stop by the "Fight the Bite" event at the State Capitol in Sacramento on Thursday, April 21st from 1:00 - 4:00pm for more information. Contact your local mosquito and vector control district to learn about events in your area.

Interactive Map

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

Total Counties with
WNV in 2016: 34

New counties highlighted in red.
Alameda, Butte, Colusa, Contra Costa, Fresno, Glenn, 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 Increased West Nile Virus Activity Statewide
SACRAMENTO - The California Department of Public Health (CDPH) is reporting increased West Nile virus activity across the state and is investigating numerous suspect cases in humans. While the first human case has not been confirmed by CDPH, a resident of Los Angeles County has symptoms consistent with West Nile virus disease. Initial tests on that patient indicate a probable West Nile virus diagnosis, which requires further testing for confirmation.
WNV Dead Bird Hotline Update
The West Nile virus and Dead Bird Hotline is staffed with live operators from 8AM to 4:30PM, Monday through Friday (beginning in late May we will also be staffed on Sundays). Call the hotline at 1-877-WNV-BIRD to report a dead bird.
- view news and press release archives -

human cases

YTD: 3 Counties: 3
There were 3 new WNV human cases reported in California this week from the following counties: Fresno (1), Los Angeles (1), and Yuba (1). These are the first WNV human cases from Fresno, Los Angeles, and Yuba counties this year.

3 human cases from 3 counties have tested positive for WNV in 2016.

 

dead birds

YTD: 715 Counties: 26
There were 59 new WNV positive dead birds reported in California this week from the following counties: Alameda (2), Butte (1), Contra Costa (1), Lake (1), Los Angeles (8), Madera (1), Orange (6), Placer (6), Sacramento (11), San Diego (9), San Joaquin (2), San Mateo (3), Santa Clara (1), Stanislaus (2), Tulare (1), and Yolo (4). This is the first WNV positive dead bird from Tulare County this year.

715 dead birds from 26 counties have tested positive for WNV in 2016.

 

mosquito samples

YTD: 1,487 Counties: 30
There were 330 new WNV positive mosquito samples reported in California this week from the following counties: Alameda (2), Butte (4), Fresno (11), Kern (6), Lake (5), Los Angeles (27), Madera (6), Orange (28), Placer (23), Riverside (3), Sacramento (41), San Bernardino (5), San Joaquin (44), San Mateo (2), Stanislaus (50), Sutter (15), Tulare (10), Yolo (47), and Yuba (1). These are the first WNV positive mosquito samples from Alameda and San Mateo counties this year.

1,487 mosquito samples from 30 counties have tested positive for WNV in 2016.

A mosquito sample may contain up to 50 individual mosquitoes.

 

sentinel chickens

YTD: 73 Counties: 11
There were 43 new WNV positive sentinel chickens reported in California this week from the following counties: Butte (4), Colusa (5), Contra Costa (2), Glenn (5), Merced (13), Sutter (5), Tehama (2), and Yuba (7). These are the first WNV positive sentinel chickens from Butte, Contra Costa, Glenn, and Yuba counties this year. This is the first indication of WNV from Colusa and Tehama counties this year.

73 sentinel chickens from 11 counties have tested positive for WNV in 2016.

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.

2003-2015 WNV Activity Summary

Element 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 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) 783 (53) 5,588 (229)
Horses 12 540 456 58 28 32 18 19 15 22 13 03 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 1,349 20,090
Mosquito samples 32 1,136 1,242 832 1,007 2,003 1,063 1,305 2,087 2849 2,528 3,340 3,329 22,753
Sentinel chickens 70 809 1,053 640 510 585 443 281 391 540 485 443 449 6,699
Squirrels - 49 48 32 26 32 10 24 24 23 03 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 Jul 29, 2016201620155Y AVG
Counties343630
Human cases3108
Dead birds715303417
Mosquito samples14871058766
Sentinel chickens734542
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2015 YTD activity -

WNV Reports

Weekly Report

07.29 Arbovirus Bulletin #21
07.29 2016 YTD WNV Activity Map
07.22 Arbovirus Bulletin #20

Humans

03.21 2015 Human WNV Incidence Report
03.21 2003-2015 WNV Case Summary
03.09 2014 Human WNV Incidence Report

Dead Birds

07.29Positive Species for 2016
07.29Reported, Tested, Positive 2016
07.29Positive Counts by City/County for 2016

Mosquitoes

07.29 AMOR - EVS Week 29
07.29 AMOR - GRAVID Week 29
07.29 AMOR - NJLT Week 29
- view report archives -