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

Case Counts by County

CountyDead birds
Alameda11
Alpine-
Amador-
Butte21
Calaveras-
Colusa-
Contra Costa27
Del Norte-
El Dorado4
Fresno6
Glenn4
Humboldt-
Imperial-
Inyo-
Kern-
Kings4
Lake4
Lassen-
Los Angeles113
Madera5
Marin5
Mariposa-
Mendocino-
Merced5
Modoc-
Mono-
Monterey-
Napa1
Nevada2
Orange78
Placer28
Plumas-
Riverside14
Sacramento409
San Benito-
San Bernardino5
San Diego255
San Francisco-
San Joaquin35
San Luis Obispo-
San Mateo11
Santa Barbara-
Santa Clara85
Santa Cruz2
Shasta3
Sierra-
Siskiyou-
Solano13
Sonoma8
Stanislaus12
Sutter10
Tehama-
Trinity-
Tulare3
Tuolumne-
Ventura30
Yolo71
Yuba4
Total1288

WNV Activity by County
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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).

Having problems with mosquitoes?

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

As of Sep 30, 2016201620155Y AVG
Counties374038
Human cases276300233
Dead birds128810161237
Mosquito samples336028902551
Sentinel chickens301330354
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2015 YTD activity -

WNV Reports

Weekly Report

09.30 Arbovirus Bulletin #30
09.30 2016 YTD WNV Activity Map
09.27 2016 US Arboviral Activity Update

Humans

09.30 2016 Human WNV Incidence Report
09.30 2003-2016 WNV Case Summary
03.21 2015 Human WNV Incidence Report

Dead Birds

09.30Positive Species for 2016
09.30Reported, Tested, Positive 2016
09.30Positive Counts by City/County for 2016

Mosquitoes

09.30 AMOR - EVS Week 38
09.30 AMOR - GRAVID Week 38
09.30 AMOR - NJLT Week 38
- view report archives -