Case Counts by County

CountyDead birds
Alameda96
Alpine-
Amador-
Butte22
Calaveras-
Colusa4
Contra Costa44
Del Norte-
El Dorado7
Fresno9
Glenn4
Humboldt2
Imperial-
Inyo-
Kern3
Kings3
Lake18
Lassen-
Los Angeles99
Madera5
Marin6
Mariposa-
Mendocino-
Merced8
Modoc-
Mono-
Monterey-
Napa12
Nevada-
Orange431
Placer40
Plumas-
Riverside1
Sacramento294
San Benito-
San Bernardino17
San Diego35
San Francisco-
San Joaquin53
San Luis Obispo-
San Mateo20
Santa Barbara2
Santa Clara925
Santa Cruz1
Shasta6
Sierra-
Siskiyou-
Solano33
Sonoma37
Stanislaus47
Sutter19
Tehama-
Trinity-
Tulare40
Tuolumne-
Ventura7
Yolo71
Yuba16
Total2437

WNV Activity by County
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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).

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

As of Dec 16, 2014201420135Y AVG
Counties404440
Human cases794375241
Dead birds24371251901
Mosquito samples334025281966
Sentinel chickens443485428
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2013 YTD activity -

WNV Reports

Weekly Report

12.16 2014 US Arboviral Activity Update
12.16 2014 YTD WNV Activity Map
12.12 Arbovirus Bulletin #42

Humans

12.16 2014 Human WNV Incidence Report
12.16 2003-2014 WNV Case Summary
08.12 2013 Human WNV Incidence Report

Dead Birds

12.16Reported, Tested, Positive 2014
12.16Positive Counts by City/County for 2014
12.16Positive Species for 2014

Mosquitoes

11.07 AMOR - EVS Week 44
11.07 AMOR - GRAVID Week 44
11.07 AMOR - NJLT Week 44
- view report archives -