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

Case Counts by County

CountyDead birds
Alameda-
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 Diego-
San Francisco-
San Joaquin-
San Luis Obispo-
San Mateo1
Santa Barbara-
Santa Clara2
Santa Cruz-
Shasta-
Sierra-
Siskiyou-
Solano-
Sonoma-
Stanislaus-
Sutter-
Tehama-
Trinity-
Tulare-
Tuolumne-
Ventura-
Yolo-
Yuba-
Total3

WNV Activity by County
Printable Version
2018 | 2017 | 2016 | 2015 | 2014
2013 | 2012 | 2011
2010 | 2009 | 2008
2007

Data on this website are updated every Friday by 4pm. Due to different reporting schedules, case totals here may not always reflect those reported by local health departments. Updates during the off season (January-April) are less frequent.
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: 2

San Mateo, and Santa Clara.

WNV Dead Bird Hotline Update
The West Nile virus and Dead Bird Hotline is staffed with live operators from mid-April to mid-October each year. During the winter months, you can still report a dead bird by using the report form on this website:

Report a Dead Bird

Although West Nile virus testing is reduced in the winter, some local vector control districts are collecting and testing birds year-round, especially crows, ravens, and magpies.

Thank you for your report!

- view news and press release archives -

human cases

YTD: 0 Counties: 0
No cases of human WNV illness have been reported positive for WNV in 2017.
 

horses

YTD: 0 Counties: 0
No horses have tested positive for WNV in 2017.
 

dead birds

YTD: 3 Counties: 2
There was 1 new WNV positive dead bird reported in California last week from San Mateo County. This is the first indication of WNV from San Mateo County this year.

3 dead birds from 2 counties have tested positive for WNV in 2017.

 

mosquito samples

YTD: 0 Counties: 0
No mosquito samples have tested positive for WNV in 2017.

A mosquito sample may contain up to 50 individual mosquitoes.

 

sentinel chickens

YTD: 0 Counties: 0
No sentinel chickens have tested positive for WNV in 2017.

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.

2003-2017 WNV Activity Summary

Element 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 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) 782 (53) 442 (19) 536 (41) 6,565 (289)
Horses 12 540 456 58 28 32 18 19 15 22 13 03 03 03 21 1,223
Dead birds 96 3,232 3,046 1,446 1,396 2,569 515 416 688 1,644 1,251 2,442 1,349 1,352 510 21,952
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 3,528 3,371 29,652
Sentinel chickens 70 809 1,053 640 510 585 443 281 391 540 485 443 449 343 305 7,347
Squirrels - 49 48 32 26 32 10 24 24 23 03 03 03 03 03 276
1 There were 20 imported human cases. 2 There were 3 imported horse cases. 3 No longer monitored.

Having problems with mosquitoes?

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

As of Feb 23, 2018201820175Y AVG
Counties232
Human cases000
Dead birds332
Mosquito samples000
Sentinel chickens000
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2017 YTD activity -

WNV Reports

Weekly Report

02.23 2018 YTD WNV Activity Map
02.16 2018 YTD SLEV Activity Map
02.02 2017 YTD WNV Activity Map

Humans

02.02 2017 Human WNV Incidence Report
02.02 2003-2017 WNV Case Summary
02.08 2016 Human WNV Incidence Report

Dead Birds

02.23Reported, Tested, Positive 2018
02.23Positive Species for 2018
02.23Positive Counts by City/County for 2018

Mosquitoes

11.09 AMOR - EVS Week 44
11.09 AMOR - GRAVID Week 44
11.09 AMOR - NJLT Week 44
- view report archives -