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

Case Counts by County

CountyDead birds
Alameda16
Alpine-
Amador-
Butte3
Calaveras-
Colusa-
Contra Costa12
Del Norte-
El Dorado2
Fresno-
Glenn-
Humboldt1
Imperial-
Inyo-
Kern-
Kings-
Lake-
Lassen-
Los Angeles10
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada-
Orange6
Placer41
Plumas-
Riverside5
Sacramento234
San Benito-
San Bernardino-
San Diego-
San Francisco-
San Joaquin12
San Luis Obispo-
San Mateo5
Santa Barbara-
Santa Clara47
Santa Cruz2
Shasta4
Sierra-
Siskiyou-
Solano-
Sonoma-
Stanislaus1
Sutter4
Tehama-
Trinity-
Tulare-
Tuolumne1
Ventura-
Yolo39
Yuba-
Total445

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
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Total Counties with
WNV in 2018: 37

Alameda, Amador, Butte, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Humboldt, Imperial, Kern, Kings, Lake, Los Angeles, Madera, Merced, Orange, Placer, Riverside, Sacramento, San Benito, San Bernardino, San Diego, San Joaquin, San Mateo, Santa Clara, Santa Cruz, Shasta, Solano, Stanislaus, Sutter, Tehama, Tulare, Tuolumne, Ventura, Yolo, and Yuba.

CDPH Confirms First Two Human West Nile Virus Deaths of 2018
SACRAMENTO - The California Department of Public Health (CDPH) announced today two confirmed deaths in California due to West Nile virus (WNV). The deceased persons were residents of Glenn county and Yuba county.

Repellent Toolkit


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human cases

YTD: 100 Counties: 25
There were 21 new WNV human cases reported in California last week from the following counties: Contra Costa (1), Lake (1), Los Angeles (10), Merced (1), Orange (2), Placer (1), Riverside (1), Stanislaus (2), and Tulare (2). This is the first WNV human case from Lake County this year.

4 WNV-related fatalities have been reported to CDPH this year from four local health jurisdictions: Glenn (1), Placer (1), Yolo (1), and Yuba (1) counties.

100 human cases from 25 counties have tested positive for WNV in 2018.

 

horses

YTD: 8 Counties: 7
There was 1 new WNV positive horse reported in California last week from Amador County. This is the first WNV positive horse from Amador County this year.

8 horses from 7 counties have tested positive for WNV in 2018.

 

dead birds

YTD: 445 Counties: 19
There were 15 new WNV positive dead birds reported in California last week from the following counties: Contra Costa (1), Los Angeles (1), Orange (1), Placer (1), Sacramento (2), San Joaquin (1), Santa Clara (4), Tuolumne (1), and Yolo (3). This is the first WNV positive dead bird from Tuolumne County this year.

445 dead birds from 19 counties have tested positive for WNV in 2018.

 

mosquito samples

YTD: 1,802 Counties: 28
There were 72 new WNV positive mosquito samples reported in California last week from the following counties: Alameda (4), Butte (1), Contra Costa (2), Fresno (5), Kern (1), Kings (2), Los Angeles (15), Madera (2), Merced (4), Placer (1), Riverside (1), Sacramento (5), San Joaquin (17), Shasta (1), Stanislaus (5), and Tulare (6).

1,802 mosquito samples from 28 counties have tested positive for WNV in 2018.

A mosquito sample may contain up to 50 individual mosquitoes.

 

sentinel chickens

YTD: 122 Counties: 14
There were 10 new WNV positive sentinel chickens reported in California last week from the following counties: Butte (1), Colusa (3), Contra Costa (2), Merced (2), Santa Clara (1), and Sutter (1).

122 sentinel chickens from 14 counties have tested positive for WNV in 2018.

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) 553 (44) 6,582 (292)
Horses 12 540 456 58 28 32 18 19 15 22 23 153 193 213 21 1,288
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 Not monitored this year.

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

As of Sep 21, 2018201820175Y AVG
Counties373940
Human cases100174231
Dead birds4453961159
Mosquito samples180231162882
Sentinel chickens122235310
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2018 YTD activity -

WNV Reports

Weekly Report

09.21 Arbovirus Bulletin #25
09.21 2018 YTD SLEV Activity Map
09.21 2018 YTD WNV Activity Map

Humans

09.10 2018 Human WNV Incidence Report
09.05 2003-2018 WNV Case Summary
03.29 2017 Human WNV Incidence Report

Dead Birds

09.21Reported, Tested, Positive 2018
09.21Positive Species for 2018
09.21Positive Counts by City/County for 2018

Mosquitoes

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