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

Case Counts by County

CountyDead birds
Alameda-
Alpine-
Amador-
Butte-
Calaveras-
Colusa-
Contra Costa-
Del Norte-
El Dorado-
Fresno-
Glenn-
Humboldt-
Imperial-
Inyo-
Kern1
Kings-
Lake-
Lassen-
Los Angeles3
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada1
Orange2
Placer-
Plumas-
Riverside1
Sacramento10
San Benito-
San Bernardino1
San Diego2
San Francisco-
San Joaquin1
San Luis Obispo-
San Mateo1
Santa Barbara-
Santa Clara-
Santa Cruz-
Shasta-
Sierra-
Siskiyou-
Solano-
Sonoma-
Stanislaus-
Sutter-
Tehama-
Trinity-
Tulare4
Tuolumne-
Ventura-
Yolo-
Yuba-
Total27

WNV Activity by County
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2017 | 2016 | 2015 | 2014
2013 | 2012 | 2011
2010 | 2009 | 2008
2007

Press Releases

West Nile Virus at Highest Level Ever in Mosquitoes

Sep 3, 2014

FOR IMMEDIATE RELEASE
PH14-078
CONTACT: Anita Gore
(916) 440-7259

Significant increase in human cases


SACRAMENTO - Dr. Ron Chapman, director of the California Department of Public Health (CDPH) and state health officer, is reminding Californians to remain vigilant against the threat of West Nile virus.

"The proportion of mosquitoes infected with West Nile virus is at the highest level ever detected in California," Chapman said. "Last week, 52 new human cases were reported to CDPH. We expect to see more people become infected as this is the time of year when the risk of infection is the highest."

So far in 2014, West Nile virus has been detected in 36 California counties. There have been 181 human cases reported to CDPH, a significant increase compared to the 101 cases reported by this time last year. Eight confirmed deaths have been reported to CDPH.

West Nile virus is transmitted to humans and animals by the bite of an infected mosquito. For most people, the risk of serious illness is low. However, some individuals - less than one percent - can develop a serious neurologic illness, such as encephalitis or meningitis. People 50 years of age or older and people with diabetes and/or high blood pressure have the greatest risk of developing serious complications.

CDPH recommends that individuals prevent exposure to mosquito bites and West Nile virus by practicing the "Three Ds:"

  1. DEET-Apply insect repellent containing DEET,picaradin, oil of lemon eucalyptus or IR3535 according to label instructions. Repellents keep the mosquitoes from biting you. DEET can be used safely on infants and children 2 months of age and older.

  2. DAWN AND DUSK - Mosquitoes bite in the early morning and evening so it is important to wear protective clothing and repellent if outside during these times. Make sure that your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens with tears or holes.

  3. DRAIN - Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property, including flower pots, old car tires, and buckets. If you know of a swimming pool that is not being properly maintained, please contact your local mosquito and vector control agency.

California's West Nile virus website includes the latest information on West Nile virus activity in the state. Californians are encouraged to report all dead birds on the website or by calling toll-free 1-877-WNV-BIRD (968-2473).

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

As of Jun 23, 2017201720165Y AVG
Counties162122
Human cases201
Dead birds27279157
Mosquito samples302264172
Sentinel chickens042
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2016 YTD activity -

WNV Reports

Weekly Report

06.23 Arbovirus Bulletin #12
06.23 2017 YTD WNV Activity Map
06.16 Arbovirus Bulletin #11

Humans

02.08 2016 Human WNV Incidence Report
02.08 2003-2016 WNV Case Summary
03.21 2015 Human WNV Incidence Report

Dead Birds

06.23Positive Counts by City/County for 2017
06.23Positive Species for 2017
06.23Reported, Tested, Positive 2017

Mosquitoes

06.23 AMOR - EVS Week 24
06.23 AMOR - GRAVID Week 24
06.23 AMOR - NJLT Week 24
- view report archives -