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

Case Counts by County

CountyDead birds
Alameda20
Alpine-
Amador-
Butte4
Calaveras-
Colusa-
Contra Costa13
Del Norte-
El Dorado2
Fresno-
Glenn-
Humboldt1
Imperial-
Inyo-
Kern1
Kings-
Lake-
Lassen-
Los Angeles19
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada-
Orange16
Placer44
Plumas-
Riverside6
Sacramento241
San Benito-
San Bernardino-
San Diego1
San Francisco-
San Joaquin16
San Luis Obispo-
San Mateo5
Santa Barbara-
Santa Clara56
Santa Cruz2
Shasta5
Sierra-
Siskiyou-
Solano-
Sonoma-
Stanislaus1
Sutter4
Tehama-
Trinity-
Tulare-
Tuolumne1
Ventura-
Yolo41
Yuba-
Total499

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 2018: 41

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

West Nile virus and Dead Bird Hotline
The West Nile virus and Dead Bird Hotline is staffed with live operators from mid-April to mid-October each year.

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.

- view news and press release archives -

human cases

YTD: 203 Counties: 31
There have been 2 new WNV human cases reported in California this week from Los Angeles (1) and Tehama (1) counties.

8 WNV-related fatalities have been reported to CDPH this year from seven local health jurisdictions: Butte (1), Glenn (1), Los Angeles (1), Orange (1), Placer (2), Yolo (1), and Yuba (1) counties.

203 human cases from 31 counties have tested positive for WNV in 2018.

 

horses

YTD: 11 Counties: 8

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

 

dead birds

YTD: 499 Counties: 21

499 dead birds from 21 counties have tested positive for WNV in 2018.

 

mosquito samples

YTD: 1,963 Counties: 29

1,963 mosquito samples from 29 counties have tested positive for WNV in 2018.

A mosquito sample may contain up to 50 individual mosquitoes.

 

sentinel chickens

YTD: 163 Counties: 16

163 sentinel chickens from 16 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.

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 Dec 14, 2018201820175Y AVG
Counties414442
Human cases203501559
Dead birds4995061378
Mosquito samples196333713217
Sentinel chickens163305405
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2018 YTD activity -

WNV Reports

Weekly Report

12.14 Arbovirus Bulletin #35
12.14 2018 YTD SLEV Activity Map
12.14 2018 YTD WNV Activity Map

Humans

12.13 2018 Human WNV Incidence Report
12.13 2003-2018 WNV Case Summary
03.29 2017 Human WNV Incidence Report

Dead Birds

12.14Reported, Tested, Positive 2018
12.14Positive Species for 2018
12.14Positive 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 -