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-
Kern1
Kings-
Lake-
Lassen-
Los Angeles3
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada1
Orange2
Placer-
Plumas-
Riverside1
Sacramento10
San Benito-
San Bernardino1
San Diego2
San Francisco-
San Joaquin1
San Luis Obispo-
San Mateo1
Santa Barbara-
Santa Clara-
Santa Cruz-
Shasta-
Sierra-
Siskiyou-
Solano-
Sonoma-
Stanislaus-
Sutter-
Tehama-
Trinity-
Tulare4
Tuolumne-
Ventura-
Yolo-
Yuba-
Total27

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

Data on this website is updated every Friday 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: 16

New counties highlighted in red.
Fresno, Kern, Kings, Los Angeles, Merced, Nevada, Orange, Riverside, Sacramento, San Bernardino, San Diego, San Joaquin, San Mateo, Stanislaus, Tulare, and Yolo.

Reporting a Dead Bird Video


Californians Urged to Remove Standing Water to Reduce Mosquitoes
SACRAMENTO - The California Department of Public Health (CDPH) urges all Californians to eliminate standing water around their homes and businesses to help reduce mosquito populations in an effort to prevent Zika and West Nile virus infections.

- view news and press release archives -

human cases

YTD: 2 Counties: 2

2 human cases from 2 counties have tested positive for WNV in 2017.

 

dead birds

YTD: 27 Counties: 11
There have been 2 new WNV positive dead birds reported in California last week from San Joaquin (1) and Tulare (1) counties. This is the first WNV positive dead bird from San Joaquin County this year.

27 dead birds from 11 counties have tested positive for WNV in 2017.

 

mosquito samples

YTD: 302 Counties: 13
There were 145 new WNV positive mosquito samples reported in California last week from the following counties: Fresno (2), Kern (5), Kings (1), Los Angeles (13), Riverside (32), San Bernardino (6), San Joaquin (28), Stanislaus (6), and Tulare (52). This is the first WNV positive mosquito sample from Kings County this year. This is the first indication of WNV from Fresno and Stanislaus counties this year.

302 mosquito samples from 13 counties 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.

2003-2016 WNV Activity Summary

Element 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 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) 6,029 (248)
Horses 12 540 456 58 28 32 18 19 15 22 13 03 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 1,352 21,442
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 26,281
Sentinel chickens 70 809 1,053 640 510 585 443 281 391 540 485 443 449 343 7,042
Squirrels - 49 48 32 26 32 10 24 24 23 03 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 Jun 23, 2017201720165Y AVG
Counties162122
Human cases201
Dead birds27279157
Mosquito samples302264172
Sentinel chickens042
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2016 YTD activity -

WNV Reports

Weekly Report

06.23 Arbovirus Bulletin #12
06.23 2017 YTD WNV Activity Map
06.16 Arbovirus Bulletin #11

Humans

02.08 2016 Human WNV Incidence Report
02.08 2003-2016 WNV Case Summary
03.21 2015 Human WNV Incidence Report

Dead Birds

06.23Positive Counts by City/County for 2017
06.23Positive Species for 2017
06.23Reported, Tested, Positive 2017

Mosquitoes

06.23 AMOR - EVS Week 24
06.23 AMOR - GRAVID Week 24
06.23 AMOR - NJLT Week 24
- view report archives -