West Nile Virus
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Prevention
Current West Nile virus Activity
Historical West Nile virus Activity
Additional Information
About West Nile virus
West Nile virus (WNV) is a disease transmitted to humans, birds, horses, and other animals, by infected mosquitoes. Mosquitoes get the disease from feeding on infected birds. They can then bite and infect more birds or can bite and infect accidental hosts like people and horses. WNV can make people and horses sick and can even cause death.
WNV It is the most common mosquito-borne disease in the United States. It can be found in all 58 counties in California, including San Diego County.
Vector Control Program (VCP) staff monitor WNV by trapping, batching, and testing mosquitoes and by testing dead birds.
VCP also protects public health by controlling
mosquitoes that can transmit WNV, which during the mosquito season
includes aerial
helicopter treatments of large bodies of water known to breed
mosquitoes. The VCP also works to educate the public on measures they
can take to keep themselves and their families safe from WNV and other
mosquito borne diseases.
The Vector Control Program encourages everyone to prevent mosquito breeding, protect themselves against mosquito bites, and to report green pools, dead birds, and high mosquito activity. You can also request an educational inspection for your home, or a presentation about WNV prevention for your group or school.
Prevent
Dumping out standing water and keeping containers dry is easiest way to control mosquitoes around your home. Mosquitoes lay their eggs in standing water and can grow into biting adults in less than a week. You can dump water out or clean and replace the water. If you cannot dump the water, you can use a bacterial larvicide that comes in liquid, dunk, or granule form. Larvicides kill mosquitoes but are safe for people, plants, and animals. Make sure to follow the directions on the label. For larger artificial sources of water, like backyard ponds, birdbaths, fountains, animal troughs, unused swimming pools, you can add mosquitofish (available free of charge) to control mosquito larvae.
Protect
Avoid mosquito bites by wearing long sleeves and pants while outdoors and by using mosquito repellent. Keep screens over doors and windows closed and free of holes or gaps.
When choosing a repellent, look for an EPA-approved active ingredient like DEET, Picaridin, IR3535, Para-menthane-diol, 2-undecanone, or Oil of Lemon Eucalyptus.
Report
You can report to the Vector Control Program:
- Green swimming pools that may be sources of mosquito breeding
- Dead birds such as crows, jays, hawks, and owls (When appropriate these will be tested for WNV)
- High mosquito activity, or other vector-related issue.
2024 West Nile Virus Positives | ||||
---|---|---|---|---|
Number of Positives to Date | Type | Date Collected | Location | Species |
1 | Bird | 1/15/2024 | Escondido | American Crow |
2 | Bird | 2/29/2024 | Escondido | Common Raven |
3 | Bird | 9/6/2024 | San Diego | American Crow |
4 | Bird | 9/16/2024 | San Diego - exact location unknown | American Crow |
5 | Bird | 9/30/2024 | Julian | American Crow |
For human cases and statewide data visit the CDPH West Nile virus homepage.
Year
| WNV Positive Mosquito Batches | WNV Positive Birds |
2023 | 1 | 14 |
2022 | 0 | 0 |
2021 | 0 | 1 |
2020 | 2 | 1 |
2019 | 0 | 2 |
2018 | 3 | 1 |
2017 | 9 | 43 |
2016 | 99 | 266 |
2015 | 49 | 367 |
2014 | 2 | 41 |
2013 | 0 | 9 |
2012 | 0 | 1 |
2011 | 1 | 0 |
2010 | 1 | 2 |
2009 | 5 | 38 |
2008 | 40 | 563 |
2007 | 5 | 118 |
2006 | 0 | 19 |
2005 | 0 | 162 |
2004 | 0 | 34 |
2003 | 0 | 5 |
For human cases and statewide data visit the CDPH West Nile virus homepage.
Additional Information
Information
about mosquitoes
Mosquito Treatment
Information - San Diego
Aerial
Larvicide Application Schedule
State of California WNV
webpage
WNV
Clinical Information - Health and Human Services
Information
for Veterinarians