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 Angeles34
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada-
Orange29
Placer-
Plumas-
Riverside23
Sacramento4
San Benito-
San Bernardino3
San Diego9
San Francisco-
San Joaquin6
San Luis Obispo-
San Mateo-
Santa Barbara-
Santa Clara-
Santa Cruz-
Shasta1
Sierra-
Siskiyou-
Solano1
Sonoma-
Stanislaus7
Sutter-
Tehama-
Trinity-
Tulare1
Tuolumne-
Ventura-
Yolo-
Yuba-
Total122

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.
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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
A total of 127 human cases have been reported this year in the following 14 counties: Alameda (1), Butte (2), Fresno (1), Los Angeles (34), Orange (34), Riverside (23), Sacramento (4), San Bernardino (3), San Diego (9), San Joaquin (6), Shasta (1), Solano (1), Stanislaus (7), and Tulare (1) counties. Of the 127 individuals, 89 (70%) developed neuroinvasive symptoms. The median age of the 127 individuals is 54 years (range: 4-84 years), and 79 (63%) are male. Two WNV-related fatalities have been reported in Orange County. In addition, 30 WNV-positive blood donation samples have been reported this year; 9 of the individuals reported symptoms and were reclassified as cases. At this time last year, 172 human cases had been reported in California.

human cases

YTD: 122 Counties: 14
There were 30 new WNV positive human cases reported in California this week from the following counties: Los Angeles (9), Orange (8), Riverside (4), San Bernardino (1), San Diego (4), San Joaquin (1), Shasta (1), and Stanislaus (2). This is the first WNV positive human case from Shasta County this year. There has been 1 WNV-related fatality from Orange County reported in California this year. 122 human cases from 14 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: 11 Counties: 4
There have been 2 new WNV positive squirrels reported in California this week from Orange (1) and San Bernardino (1) counties. This is the first WNV positive squirrel from Orange County this year. 11 squirrels from 4 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 08/29/08 20072008
Counties4839
Human cases173122
Horses185
Dead birds8231456
Mosquito samples6831101
Sentinel chickens189109
Squirrels1011
2007 YTD - Year to date corresponds to the same time last year.

- view all 2007 YTD activity -

WNV Reports

Weekly Report

08.29 2008 YTD WNV Activity Map
08.292008 WNV Activity by County
08.25 Comparative Line Graphs of West Nile Virus Activity

Humans

08.29 2008 Human WNV Case Linelist
08.29 2008 Summary Table of Human Infection
08.26 2004-2008 WNV Case Summary

Dead Birds

08.29Reported, Tested, Positive 2007 YTD
08.29Positive Counts by City/County for 2008
08.29Reported, 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 -