Case Counts by County

CountyHuman cases
Alameda1
Alpine-
Amador-
Butte2
Calaveras-
Colusa-
Contra Costa-
Del Norte-
El Dorado-
Fresno1
Glenn-
Humboldt-
Imperial-
Inyo-
Kern-
Kings-
Lake-
Lassen-
Los Angeles28
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada-
Orange27
Placer-
Plumas-
Riverside21
Sacramento4
San Benito-
San Bernardino2
San Diego5
San Francisco-
San Joaquin5
San Luis Obispo-
San Mateo-
Santa Barbara-
Santa Clara-
Santa Cruz-
Shasta-
Sierra-
Siskiyou-
Solano1
Sonoma-
Stanislaus5
Sutter-
Tehama-
Trinity-
Tulare1
Tuolumne-
Ventura-
Yolo-
Yuba-
Total103

WNV Activity by County
Printable Version
2008 | 2007

Human data is updated every Tuesday and Friday by 4pm. Dead bird and squirrel data are updated every Wednesday by 4pm. Horse, mosquito and sentinel chicken data are updated every Friday by 4pm.
- View Printable Map -

Total Counties with
WNV in 2008: 39

New counties highlighted in red.
Alameda, Amador, Butte, Calaveras, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Imperial, Kern, Lake, Los Angeles, Marin, Mendocino, Merced, Monterey, Nevada, Orange, Placer, Riverside, Sacramento, San Bernardino, San Diego, San Joaquin, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Shasta, Solano, Sonoma, Stanislaus, Sutter, Tehama, Tulare, Ventura, Yolo, and Yuba.

Latest WNV News
CALIFORNIA DEPARTMENT OF PUBLIC HEALTH ANNOUNCES FIRST DEATH FROM WEST NILE VIRUS IN 2008 08/25/08
SACRAMENTO - Dr. Mark Horton, director of the California Department of Public Health (CDPH), announced today that West Nile virus (WNV) has claimed the life of an elderly woman in Orange County. She is the first death this year in California from complications associated with the virus.
First Confirmed Case of West Nile Virus in Horses for 2008 06/24/08
The first positive equine case of West Nile Virus (WNV) in California in 2008 has been reported in Riverside County. The affected horse, a 15-year-old quarter horse gelding, died of WNV disease complications.
- view news and press release archives -

National Activity
As of August 19, 2008, 236 human cases had been reported nationwide this year in the following 28 states: Alabama (1), Arizona (5), Arkansas (5), California (73), Colorado (20), Connecticut (1), Idaho (8), Iowa (1), Louisiana (6), Michigan (1), Minnesota (10), Mississippi (33), Missouri (3), Nebraska (2), Nevada (2), New York (2), North Dakota (14), Ohio (1), Oklahoma (5), Oregon (3), Pennsylvania (1), South Dakota (14), Tennessee (6), Texas (14), Utah (2), West Virginia (1), Wisconsin (1) and Wyoming (1). Of the 236 individuals, 97 (41%) had neuroinvasive illness. Two fatalities have been reported in Arizona and Mississippi. At this time last year, 576 human cases had been reported nationwide.

human cases

YTD: 103 Counties: 13
There were 11 new WNV positive human cases reported in California this week from the following counties: Los Angeles (3), Orange (6), and Riverside (2). There has been 1 WNV-related fatality from Orange County reported in California this year. 103 human cases from 13 counties have tested positive for WNV in 2008.
 

horses

YTD: 5 Counties: 4
There has been 1 WNV-related horse euthanized or died in California this year from Riverside county. 5 horses from 4 counties have tested positive for WNV in 2008.
 

dead birds

YTD: 1,456 Counties: 36
There were 161 new WNV positive dead birds reported in California this week from the following counties: Contra Costa (8), Fresno (1), Glenn (3), Los Angeles (59), Orange (16), Riverside (4), Sacramento (5), San Bernardino (23), San Diego (33), San Joaquin (2), San Mateo (1), Santa Barbara (1), Stanislaus (2), Ventura (2), and Yolo (1). This is the first indication of WNV from Santa Barbara County this year. 1,456 dead birds from 36 counties have tested positive for WNV in 2008.
 

mosquito samples

YTD: 1,101 Counties: 24
There were 195 new WNV positive mosquito samples reported in California last week from the following counties: Alameda (1), Butte (3), Contra Costa (7), Fresno (5), Imperial (6), Lake (1), Los Angeles (39), Orange (4), Placer (3), Riverside (5), Sacramento (45), San Bernardino (26), San Diego (1), San Joaquin (33), Stanislaus (5), Tulare (8), and Yolo (3). This is the first WNV positive mosquito sample from Alameda County this year. 1,101 mosquito samples from 24 counties have tested positive for WNV in 2008.
 

sentinel chickens

YTD: 109 Counties: 12
There were 46 new WNV positive sentinel chickens reported in California last week from the following counties: Los Angeles (16), Orange (3), Riverside (14), Sacramento (4), San Bernardino (7), San Joaquin (1), and Sutter (1). These are the first WNV positive sentinel chickens from Orange, San Joaquin, and Sutter counties this year. 109 sentinel chickens from 12 counties have tested positive for WNV in 2008.
 

squirrels

YTD: 10 Counties: 3
There was 1 new WNV positive squirrel reported in California this week from San Bernardino County. 10 squirrels from 3 counties have tested positive for WNV in 2008.

Be a West Nile Watcher

Help us track down the West Nile Virus by reporting all dead birds and squirrels. Call 1-877-968-2473 to report a dead bird or squirrel or you can submit an online report.

2003-2007 WNV Activity Summary

Element 2003 2004 2005 2006 2007 Total
Human cases (fatal) 31 (0) 779 (29) 880 (19) 278 (7) 380 (21) 2,320 (76)
Click here for a printable version of the 2004-2008 WNV Case Summary
Element 2003 2004 2005 2006 2007 Total
Horses 12 540 456 58 28 1,083
Dead birds 96 3,232 3,046 1,446 1,395 9,215
Mosquito samples 32 1,136 1,242 832 1,007 4,249
Sentinel chickens 70 809 1,053 640 510 3,082
Squirrels - 49 48 32 26 155
1 There were 20 imported human cases. 2 There were 3 imported horse cases.

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Compared to 2007 YTD

As of 08/27/08 20072008
Counties4839
Human cases173103
Horses165
Dead birds8231456
Mosquito samples6831101
Sentinel chickens189109
Squirrels1010
2007 YTD - Year to date corresponds to the same time last year.

- view all 2007 YTD activity -

WNV Reports

Weekly Report

08.27 2008 YTD WNV Activity Map
08.272008 WNV Activity by County
08.25 Comparative Line Graphs of West Nile Virus Activity

Humans

08.26 2008 Human WNV Case Linelist
08.26 2008 Summary Table of Human Infection
08.26 2004-2008 WNV Case Summary

Dead Birds

08.27Reported, Tested, Positive 2007 YTD
08.27Positive Counts by City/County for 2008
08.27Reported, Tested, Positive 2008

Mosquitoes

08.22 AMOR - NJLT 5 Year Average Week 33
08.22 AMOR - NJLT Week 33
08.22 AMOR - GRAVID Week 33

Sentinel Chickens

08.22 Submission Data for 8/18/08 - 8/22/08
08.15 Submission Data for 8/11/08 - 8/15/08
08.08 Submission Data for 8/4/08 - 8/8/08

Horses

11.02 Confirmed Equine Cases
10.04 2007 Equine WNV Result Map
- view report archives -