Case Counts by County

CountyDead birds
Alameda5
Alpine-
Amador-
Butte17
Calaveras-
Colusa3
Contra Costa2
Del Norte-
El Dorado1
Fresno-
Glenn3
Humboldt2
Imperial-
Inyo-
Kern1
Kings1
Lake2
Lassen-
Los Angeles3
Madera1
Marin1
Mariposa-
Mendocino-
Merced1
Modoc-
Mono-
Monterey-
Napa-
Nevada1
Orange5
Placer4
Plumas-
Riverside16
Sacramento27
San Benito-
San Bernardino1
San Diego65
San Francisco-
San Joaquin7
San Luis Obispo-
San Mateo7
Santa Barbara-
Santa Clara49
Santa Cruz-
Shasta3
Sierra-
Siskiyou-
Solano4
Sonoma3
Stanislaus8
Sutter10
Tehama-
Trinity1
Tulare18
Tuolumne-
Ventura2
Yolo23
Yuba4
Total301

WNV Activity by County
Printable Version
2015 | 2014 | 2013
2012 | 2011 | 2010
2009 | 2008 | 2007

News

CDPH Reports First Human West Nile Virus Case of 2011

Jul 22, 2011

CONTACT: Al Lundeen or Melinda Beer (916) 440-7259

SACRAMENTO - The California Department of Public Health (CDPH) today reported a man in Santa Barbara County is the first confirmed human case of West Nile virus infection in California this year. The man was hospitalized, but is now recovering at home.

"With the first confirmed human illness from West Nile virus this year, we are intensifying our surveillance for the virus with the help of all counties," said CDPH Chief Deputy Director Kathleen Billingsley. "To protect against West Nile virus, the most important step people can take is avoiding mosquito bites."

West Nile virus is most commonly transmitted to humans and animals by the bite of a mosquito harboring the virus. The risk of serious illness to most people is low. However, some individuals - less than 1 percent - will develop serious neurologic illness such as encephalitis or meningitis. People 50 years of age and older have a higher chance of getting sick and are more likely to develop serious symptoms. Recent data also indicate that those with diabetes and/or hypertension are at greatest risk for serious illness.

To date in 2011, West Nile virus has been detected in 14 other California counties.

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

  • 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.
  • DRESS - Wear clothing that reduces the risk of skin exposure to mosquito bites.
  • DAWN AND DUSK - Mosquitoes 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.
  • 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 West Nile virus website includes the latest information on West Nile virus activity in the state. Californians are encouraged to report all dead birds and dead tree squirrels on the website or by calling toll-free 1-877-WNV-BIRD (968-2473).

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

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

As of Jul 31, 2015201520145Y AVG
Counties363527
Human cases8187
Dead birds301875386
Mosquito samples1058977641
Sentinel chickens453938
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2014 YTD activity -

WNV Reports

Weekly Report

08.04 2015 US Arboviral Activity Update
07.31 Arbovirus Bulletin #22
07.31 2015 YTD WNV Activity Map

Humans

07.29 2015 Human WNV Incidence Report
07.29 2003-2015 WNV Case Summary
03.09 2014 Human WNV Incidence Report

Dead Birds

07.31Positive Species for 2015
07.31Positive Counts by City/County for 2015
07.31Reported, Tested, Positive 2015

Mosquitoes

07.31 AMOR - EVS Week 29
07.31 AMOR - GRAVID Week 29
07.31 AMOR - NJLT Week 29
- view report archives -