Case Counts by County

CountyHuman cases
Alameda-
Alpine-
Amador-
Butte-
Calaveras-
Colusa-
Contra Costa-
Del Norte-
El Dorado-
Fresno1
Glenn-
Humboldt-
Imperial-
Inyo-
Kern-
Kings-
Lake-
Lassen-
Los Angeles3
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada-
Orange2
Placer-
Plumas-
Riverside-
Sacramento-
San Benito-
San Bernardino-
San Diego1
San Francisco-
San Joaquin1
San Luis Obispo-
San Mateo-
Santa Barbara-
Santa Clara-
Santa Cruz-
Shasta-
Sierra-
Siskiyou-
Solano-
Sonoma-
Stanislaus2
Sutter-
Tehama-
Trinity-
Tulare1
Tuolumne-
Ventura-
Yolo-
Yuba-
Total11

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: 28

Amador, Butte, Contra Costa, El Dorado, Fresno, Glenn, Imperial, Kern, Los Angeles, Monterey, Nevada, Orange, Placer, Riverside, Sacramento, San Bernardino, San Diego, San Joaquin, San Mateo, Santa Clara, Shasta, Solano, Stanislaus, Sutter, Tulare, Ventura, Yolo, and Yuba.

Latest WNV News
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.
CALIFORNIA DEPARTMENT OF PUBLIC HEALTH ANNOUNCES FIRST CONFIRMED HUMAN WEST NILE VIRUS CASE IN 2008 06/20/08
SACRAMENTO - Dr. Mark Horton, director of the California Department of Public Health (CDPH), today announced that a Tulare County woman has tested positive for West Nile virus (WNV) infection, the first reported human case in California this year. She was not hospitalized and is recovering.
- view news and press release archives -

human cases

YTD: 11 Counties: 7
There were 5 new WNV positive human cases reported in California this week from the following counties: Fresno (1), Los Angeles (3), and San Diego (1). These are the first WNV positive human cases from Fresno, Los Angeles, and San Diego counties this year. There have been 0 WNV-related fatalities reported in California this year. 11 human cases from 7 counties have tested positive for WNV in 2008.
 

horses

YTD: 3 Counties: 3
There was 1 new WNV positive horse reported in California this week from Fresno County. This is the first WNV positive horse from Fresno County this year. There has been 1 WNV-related horse euthanized or died in California this year from Riverside county. 3 horses from 3 counties have tested positive for WNV in 2008.
 

dead birds

YTD: 557 Counties: 26
There were 122 new WNV positive dead birds reported in California this week from the following counties: Butte (4), Contra Costa (5), Kern (1), Los Angeles (17), Monterey (1), Orange (21), Riverside (4), Sacramento (17), San Bernardino (8), San Diego (27), San Joaquin (10), Solano (1), Stanislaus (2), Tulare (1), Ventura (2), and Yolo (1). This is the first WNV positive dead bird from Yolo County this year. 557 dead birds from 26 counties have tested positive for WNV in 2008.
 

mosquito samples

YTD: 292 Counties: 19
There were 137 new WNV positive mosquito samples reported in California last week from the following counties: Contra Costa (3), Fresno (5), Los Angeles (11), Orange (48), Placer (1), Riverside (13), Sacramento (13), San Bernardino (18), San Diego (3), San Joaquin (10), Stanislaus (2), Sutter (5), Tulare (3), Yolo (1), and Yuba (1). This is the first indication of WNV from Placer, Yolo, and Yuba counties this year. 292 mosquito samples from 19 counties have tested positive for WNV in 2008.
 

sentinel chickens

YTD: 8 Counties: 5
There have been 2 new WNV positive sentinel chickens reported in California last week from San Diego (2) counties. This is the first WNV positive sentinel chicken from San Diego County this year. 8 sentinel chickens from 5 counties have tested positive for WNV in 2008.
 

squirrels

YTD: 3 Counties: 2
There have been 2 new WNV positive squirrels reported in California last week from Contra Costa (2) counties. This is the first WNV positive squirrel from Contra Costa County this year. 3 squirrels from 2 counties have tested positive for WNV in 2008.

National Activity
As of July 22, 2008, 43 human cases had been reported nationwide this year in the following 14 states: Alabama (1), Arizona (1), Arkansas (2), California (6), Colorado (2), Connecticut (1), Louisiana (2), Mississippi (9), North Dakota (5), Oklahoma (3), South Dakota (3), Tennessee (1), Texas (6), and Utah (1). Of the 43 individuals, 16 (37%) had neuroinvasive illness. No cases have resulted in fatalities. At this time last year, 122 human cases had been reported nationwide.

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.

Locate Your Local Mosquito and Vector Control Agency
Search by Zip Code

Compared to 2007 YTD

As of 07/24/08 20072008
Counties3828
Human cases4311
Horses53
Dead birds426557
Mosquito samples223292
Sentinel chickens218
Squirrels53
2007 YTD - Year to date corresponds to the same time last year.

- view all 2007 YTD activity -

WNV Reports

Weekly Report

07.24 2008 YTD WNV Activity Map
07.242008 WNV Activity by County
07.21 Comparative Line Graphs of West Nile Virus Activity

Humans

07.22 2008 Human WNV Case Linelist
07.22 2008 Summary Table of Human Infection
07.22 2004-2008 WNV Case Summary

Dead Birds

07.24Reported, Tested, Positive 2007 YTD
07.24Positive Counts by City/County for 2008
07.24Reported, Tested, Positive 2008

Mosquitoes

07.18 Submission Data for 7/14/08 - 7/18/08
07.18 AMOR - NJLT 5 Year Average Week 28
07.18 AMOR - NJLT Week 28

Sentinel Chickens

07.18 Submission Data for 7/14/08 - 7/18/08
07.11 Submission Data for 7/7/08 - 7/11/08
07.03 Submission Data for 6/30/08 - 7/03/08

Horses

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