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

Case Counts by County

CountyDead birds
Alameda1
Alpine-
Amador-
Butte4
Calaveras-
Colusa1
Contra Costa10
Del Norte-
El Dorado1
Fresno5
Glenn2
Humboldt1
Imperial-
Inyo-
Kern3
Kings1
Lake3
Lassen-
Los Angeles59
Madera1
Marin-
Mariposa-
Mendocino-
Merced1
Modoc-
Mono-
Monterey1
Napa-
Nevada1
Orange37
Placer2
Plumas-
Riverside29
Sacramento65
San Benito-
San Bernardino37
San Diego22
San Francisco1
San Joaquin6
San Luis Obispo-
San Mateo1
Santa Barbara-
Santa Clara7
Santa Cruz1
Shasta2
Sierra-
Siskiyou-
Solano2
Sonoma2
Stanislaus4
Sutter2
Tehama-
Trinity-
Tulare8
Tuolumne-
Ventura1
Yolo6
Yuba6
Total336

WNV Activity by County
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2010 | 2009 | 2008
2007

News

CDPH REPORTS FIRST HUMAN WEST NILE VIRUS FATALITY OF 2010

Sep 16, 2010

SACRAMENTO - Dr. Mark Horton, director of the California Department of Public Health announced today that West Nile virus (WNV) has claimed the life of an elderly woman in Fresno County. She is the first death this year in California from complications associated with the virus.

"This unfortunate death reminds us that we must take precautions to protect ourselves and our families from mosquito bites," Horton said. "The risk of WNV transmission continues well into the fall. We should all be taking all appropriate steps to avoid mosquito bites."

WNV is transmitted to humans and animals through a mosquito bite. Mosquitoes become infected when they feed on infected birds. Despite this fatality, the number of reported WNV illnesses in California is lower than last year. In 2009, for the same period this year, there were 47 human cases. This year 45 people in 11 California counties have been diagnosed with WNV.

Most individuals who are infected with WNV will not experience any illness. However, individuals 50 years of age and older have a higher chance of getting sick and are more likely to develop serious symptoms when infected with WNV. Recent data also indicate that those with diabetes and/or hypertension are at greatest risk for serious illness.

Horton said that the most effective ways for individuals to prevent exposure to mosquito bites and WNV are to remember the “Four D’s”:


  1. DEET – Apply inspect 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. DRESS – Wear clothing that reduces the risk of skin exposure.

  3. DAWN AND DUSK – Mosquitoes that carry WNV bite in the early morning and evening so it is important to wear repellent at this time. Make sure that your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens with tears or holes.

  4. DRAIN – Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property, including flower pots, old car tires, rain gutters and pet bowls. If you have a pond, use mosquito fish (available from your local mosquito and vector control agency) or commercially available products to eliminate mosquito larvae.

California’s WNV Web site (http://westnile.ca.gov/) includes the latest information on WNV activity in the state. Californians are encouraged to report all dead birds and dead tree squirrels on the Web site 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 Sep 22, 2017201720165Y AVG
Counties423739
Human cases174234226
Dead birds33612381262
Mosquito samples297931902633
Sentinel chickens204280301
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2016 YTD activity -

WNV Reports

Weekly Report

09.22 2017 YTD WNV Activity Map
09.19 2017 US Arboviral Activity Update
09.15 Arbovirus Bulletin #24

Humans

09.20 2003-2017 WNV Case Summary
09.17 2017 Human WNV Incidence Report
02.08 2016 Human WNV Incidence Report

Dead Birds

09.18Positive Counts by City/County for 2017
09.18Positive Species for 2017
09.18Reported, Tested, Positive 2017

Mosquitoes

09.15 AMOR - EVS Week 36
09.15 AMOR - GRAVID Week 36
09.15 AMOR - NJLT Week 36
- view report archives -