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-
Butte2
Calaveras-
Colusa1
Contra Costa5
Del Norte-
El Dorado1
Fresno2
Glenn-
Humboldt-
Imperial-
Inyo-
Kern3
Kings1
Lake1
Lassen-
Los Angeles32
Madera-
Marin-
Mariposa-
Mendocino-
Merced1
Modoc-
Mono-
Monterey1
Napa-
Nevada1
Orange15
Placer1
Plumas-
Riverside23
Sacramento40
San Benito-
San Bernardino27
San Diego14
San Francisco-
San Joaquin6
San Luis Obispo-
San Mateo1
Santa Barbara-
Santa Clara5
Santa Cruz1
Shasta-
Sierra-
Siskiyou-
Solano1
Sonoma-
Stanislaus3
Sutter1
Tehama-
Trinity-
Tulare8
Tuolumne-
Ventura-
Yolo1
Yuba4
Total203

WNV Activity by County
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2010 | 2009 | 2008
2007

Press Releases

CDPH Confirms First Human West Nile Virus Illness of 2017

Apr 28, 2017


SACRAMENTO - The California Department of Public Health (CDPH) announced the first confirmed illness in California due to West Nile virus (WNV). The illness occurred in Kings County.

"West Nile virus activity in the state is increasing, so I urge Californians to take every possible precaution to protect against mosquito bites", said CDPH Director and State Public Health Officer Dr. Karen Smith.

This year to date, West Nile virus activity has been detected in three dead birds, one each from San Mateo, Orange, and San Diego counties. Heavy rains this winter in California have contributed to an increase in mosquito breeding sites. It is not known what impact the wet weather may have on the actual virus transmission risk in humans. So far this season, West Nile activity is within expected levels.
West Nile virus is influenced by many factors, including climate, the number and types of birds and mosquitoes in an area and the level of West Nile immunity in birds. West Nile virus is transmitted to humans and animals by the bite of an infected mosquito. The risk of serious illness to most people is low. However, some individuals - less than 1 percent - can develop serious neurologic illnesses such as encephalitis or meningitis.

People 50 years of age and older, and individuals with diabetes or hypertension, have a higher chance of getting sick and are more likely to develop complications.
CDPH recommends that individuals protect against mosquito bites and WNV 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. Insect repellents should not be used on children under two months of age.

2. DAWN AND DUSK - Mosquitoes usually bite in the early morning and evening so it is important to wear proper 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 that have tears or holes.

3. DRAIN - Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property, by emptying flower pots, old car tires, buckets, and other containers. 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 WNV activity in the state. Californians are encouraged to report 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 Aug 18, 2017201720165Y AVG
Counties323536
Human cases414656
Dead birds2031010872
Mosquito samples204925651820
Sentinel chickens92161149
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2016 YTD activity -

WNV Reports

Weekly Report

08.18 Arbovirus Bulletin #20
08.18 2017 YTD SLEV Activity Map
08.18 2017 YTD WNV Activity Map

Humans

08.16 2017 Human WNV Incidence Report
08.16 2003-2017 WNV Case Summary
02.08 2016 Human WNV Incidence Report

Dead Birds

08.18Positive Counts by City/County for 2017
08.18Positive Species for 2017
08.18Reported, Tested, Positive 2017

Mosquitoes

08.18 AMOR - EVS Week 32
08.18 AMOR - GRAVID Week 32
08.18 AMOR - NJLT Week 32
- view report archives -