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

Case Counts by County

CountyDead birds
Alameda1
Alpine-
Amador-
Butte2
Calaveras-
Colusa1
Contra Costa5
Del Norte-
El Dorado1
Fresno2
Glenn-
Humboldt-
Imperial-
Inyo-
Kern3
Kings1
Lake1
Lassen-
Los Angeles32
Madera-
Marin-
Mariposa-
Mendocino-
Merced1
Modoc-
Mono-
Monterey1
Napa-
Nevada1
Orange15
Placer1
Plumas-
Riverside23
Sacramento40
San Benito-
San Bernardino27
San Diego14
San Francisco-
San Joaquin6
San Luis Obispo-
San Mateo1
Santa Barbara-
Santa Clara5
Santa Cruz1
Shasta-
Sierra-
Siskiyou-
Solano1
Sonoma-
Stanislaus3
Sutter1
Tehama-
Trinity-
Tulare8
Tuolumne-
Ventura-
Yolo1
Yuba4
Total203

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: 32

New counties highlighted in red.
Alameda, Butte, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Inyo, Kern, Kings, Lake, Los Angeles, Madera, Merced, Monterey, Nevada, Orange, Placer, Riverside, Sacramento, San Bernardino, San Diego, San Joaquin, San Mateo, Santa Clara, Santa Cruz, Solano, Stanislaus, Sutter, Tulare, Yolo, and Yuba.

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: 41 Counties: 9
There were 19 new WNV human cases reported in California last week from the following counties: Butte (1), Kern (3), Los Angeles (9), Riverside (1), San Bernardino (1), San Joaquin (1), Stanislaus (2), and Tulare (1). These are the first WNV human cases from Butte, Riverside, San Joaquin, Stanislaus, and Tulare counties this year.

41 human cases from 9 counties have tested positive for WNV in 2017.

 

dead birds

YTD: 203 Counties: 29
There were 32 new WNV positive dead birds reported in California last week from the following counties: Los Angeles (5), Monterey (1), Orange (4), Riverside (1), Sacramento (3), San Bernardino (5), San Diego (5), Santa Clara (3), Stanislaus (1), Sutter (1), Yolo (1), and Yuba (2). These are the first WNV positive dead birds from Sutter and Yolo counties this year. This is the first indication of WNV from Monterey County this year.

203 dead birds from 29 counties have tested positive for WNV in 2017.

 

mosquito samples

YTD: 2,049 Counties: 24
There were 235 new WNV positive mosquito samples reported in California last week from the following counties: Butte (11), Contra Costa (1), Fresno (12), Inyo (1), Kern (11), Kings (19), Lake (3), Los Angeles (49), Madera (4), Merced (4), Orange (22), Placer (5), Riverside (7), Sacramento (4), San Bernardino (16), San Joaquin (10), Stanislaus (12), Sutter (2), Tulare (31), Yolo (8), and Yuba (3).

2,049 mosquito samples from 24 counties have tested positive for WNV in 2017.

A mosquito sample may contain up to 50 individual mosquitoes.

 

sentinel chickens

YTD: 92 Counties: 9
There were 34 new WNV positive sentinel chickens reported in California last week from the following counties: Butte (7), Contra Costa (4), Lake (1), Los Angeles (5), Merced (8), Solano (1), Sutter (7), and Yuba (1). These are the first WNV positive sentinel chickens from Contra Costa, Lake, Solano, and Sutter counties this year.

92 sentinel chickens from 9 counties 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.

Having problems with mosquitoes?

Locate your local mosquito and vector control agency
Search by Zip Code




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

As of Aug 18, 2017201720165Y AVG
Counties323536
Human cases414656
Dead birds2031010872
Mosquito samples204925651820
Sentinel chickens92161149
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2016 YTD activity -

WNV Reports

Weekly Report

08.18 Arbovirus Bulletin #20
08.18 2017 YTD SLEV Activity Map
08.18 2017 YTD WNV Activity Map

Humans

08.16 2017 Human WNV Incidence Report
08.16 2003-2017 WNV Case Summary
02.08 2016 Human WNV Incidence Report

Dead Birds

08.18Positive Counts by City/County for 2017
08.18Positive Species for 2017
08.18Reported, Tested, Positive 2017

Mosquitoes

08.18 AMOR - EVS Week 32
08.18 AMOR - GRAVID Week 32
08.18 AMOR - NJLT Week 32
- view report archives -