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

Case Counts by County

CountyDead birds
Alameda-
Alpine-
Amador-
Butte-
Calaveras-
Colusa-
Contra Costa-
Del Norte-
El Dorado-
Fresno-
Glenn-
Humboldt-
Imperial-
Inyo-
Kern1
Kings-
Lake-
Lassen-
Los Angeles3
Madera-
Marin-
Mariposa-
Mendocino-
Merced-
Modoc-
Mono-
Monterey-
Napa-
Nevada1
Orange2
Placer-
Plumas-
Riverside1
Sacramento10
San Benito-
San Bernardino1
San Diego2
San Francisco-
San Joaquin-
San Luis Obispo-
San Mateo1
Santa Barbara-
Santa Clara-
Santa Cruz-
Shasta-
Sierra-
Siskiyou-
Solano-
Sonoma-
Stanislaus-
Sutter-
Tehama-
Trinity-
Tulare3
Tuolumne-
Ventura-
Yolo-
Yuba-
Total25

WNV Activity by County
Printable Version
2017 | 2016 | 2015 | 2014
2013 | 2012 | 2011
2010 | 2009 | 2008
2007

Repellent Info

Last Updated: Mar 8, 2008

  • Why Should I Use Mosquito Repellent?
  • Insect repellent helps reduce your exposure to mosquito bites that may carry West Nile virus or other diseases, and allows you to continue to play, work, and enjoy the outdoors with a lower risk of disease.

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  • When Should I Use Mosquito Repellent?
  • Apply repellents when you are going to be outdoors and will be at risk for being bitten by mosquitoes, especially around dawn and dusk when mosquitoes are most active. If you're outside during these hours pay special attention to using repellent. The safest decision is to use repellent whenever you are outdoors, even if it is only for a few minutes.

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  • Which Mosquito Repellents Work Best?
  • A wide variety of insect repellents are available. The U.S. Centers for Disease Control and Prevention (CDC) recommends using only products containing active ingredients that are registered with the U.S. Environmental Protection Agency (EPA) for use as repellents. Registered products have been reviewed and approved for safety and effectiveness when used according label instructions. According to the CDC, the most effective repellents contain one of the following EPA registered active ingredients:
    • DEET (N,N-diethyl-m-toluamide)
    • Picaridin or KBR 3023 (2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester)
    • Oil of lemon eucalyptus or PMD (para-Menthane-3,8-diol)
    • IR3535 (3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester)
    For more information on these active ingredients, please visit the EPA Website.

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  • How Do I Choose a Repellent?
  • Repellents are available in different concentrations. A product with a higher percentage of active ingredient (such as DEET) doesn't work better, it just lasts longer between applications. Choose a repellent that will provide protection for the amount of time you will be outdoors. You should use a higher- percentage product if you will be outdoors for several hours, or will be sweating, physically active, or getting wet. If your time outdoors will be limited, use a lower-percentage product; you can always re-apply if you are outdoors longer than expected. If you use a DEET-based product, one with a concentration of 30% is fine for most situations. To reduce the risk of adverse effects, you should use the lowest concentration product you can for your situation.

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  • Are Repellents Safe?
  • DEET is the most widely available and tested repellent. Products containing DEET are very safe when used according to the directions. Because DEET is so widely used, a great deal of testing has been done. To read more information about DEET safety see the National Pesticide Information Center [NPIC], EPA re-registration eligibility decision fact sheet (npic.orst.edu/factsheets/DEETgen.pdf).

    General guidelines for using repellents safely:

    • Always follow the instructions on the product label.
    • Apply lightly but cover all exposed skin.
    • Don't apply repellent under clothing. You can apply repellent on clothing, but read the label first; some products stain fabric.
    • Do not spray aerosol or pump products in enclosed areas.
    • Do not apply aerosol or pump products directly to your face. Spray your hands and then rub them carefully over the face, avoiding eyes and mouth.
    • Do not apply repellent to cuts, wounds, or irritated skin.
    • Wash treated skin with soap and water after returning indoors.

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  • Can Repellents be used on Children?
  • You can use DEET products on children and on infants over two months old. The American Academy of Pediatrics (AAP) recommends using DEET products with a concentration of 30% or less on children. Picaridin and oil of lemon eucalyptus products can also be used on children but check the label-some should not be used on children under 3 years. When using repellents on children, apply to your own hands first and then put it on the child. Don't apply repellent to children's hands as they may put them in their mouth.

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  • Can Repellents be used on Pregnant or Nursing Women?
  • The EPA does not recommend any additional precautions for using registered repellents on pregnant or lactating women.

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  • What if I Have a Reaction to a Repellent?
  • Use of these products may cause skin reactions in rare cases. Cases of serious reactions to products containing DEET have been related to misuse of the product, such as swallowing, using over broken skin, and using for multiple days without washing skin in between use, for example. Whenever possible, wash skin between applications of repellent.

    If you suspect you or your child is having a reaction to a repellent, wash the skin and remove treated clothing. Then call your doctor or the local poison control center at: 1-800-222-1222.

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  • Where Can I Get More Information About Repellents?
  • For more information about using repellents safely please consult the EPA Web site ( http://www.epa.gov/pesticides/factsheets/alpha_fs.htm ) or consult the National Pesticide Information Center (NPIC), which is cooperatively sponsored by Oregon State University and the U.S. EPA. NPIC can be reached at http://npic.orst.edu or 1-800-858-7378.

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

As of Jun 16, 2017201720165Y AVG
Counties141918
Human cases200
Dead birds25193106
Mosquito samples157185110
Sentinel chickens021
YTD - Year to date corresponds to the same time last year or last five years.

- view all 2016 YTD activity -

WNV Reports

Weekly Report

06.16 Arbovirus Bulletin #11
06.16 2017 YTD WNV Activity Map
06.09 Arbovirus Bulletin #10

Humans

02.08 2016 Human WNV Incidence Report
02.08 2003-2016 WNV Case Summary
03.21 2015 Human WNV Incidence Report

Dead Birds

06.16Positive Counts by City/County for 2017
06.16Positive Species for 2017
06.16Reported, Tested, Positive 2017

Mosquitoes

06.15 AMOR - EVS Week 23
06.15 AMOR - GRAVID Week 23
06.15 AMOR - NJLT Week 23
- view report archives -