West Nile Virus
West Nile virus is a disease most often spread to people through the bite of an infected mosquito. Public Health closely monitors and responds to WNV activity. WNV activity typically begins in summer and continues into fall.
In California, the West Nile virus is primarily spread by Culex mosquitoes, especially Culex tarsalis and Culex pipiens. These mosquitoes are most active from dusk to dawn and prefer to lay their eggs in standing water. While they typically feed on birds, they can also bite people and other animals, spreading the virus in the process. By reducing mosquito breeding sites and protecting yourself from bites, you can help stop the spread of West Nile virus.
What are the symptoms?
Most people infected with West Nile virus don’t feel sick. However, about 1 in 5 will develop symptoms such as:- Fever
- Headache
- Body aches
- Nausea or vomiting
- Skin rash
In rare cases, the virus can affect the nervous system, leading to more serious illnesses like encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes around the brain and spinal cord).
People over 55 or those with certain health conditions are at higher risk of severe symptoms, which may include:- Tremors
- Vision loss
- Numbness
- Paralysis
Recovery from severe illness may take weeks or even months; in some cases, symptoms can be long-lasting or permanent. Very serious cases can be fatal.
How Can I Reduce the Risk?
You can reduce the risk of exposure to mosquito bites and West Nile Virus by following these methods:- Use insect repellent – Choose an EPA-registered product and apply it when spending time outdoors.
- Wear long sleeves and pants – Especially during peak mosquito hours (dawn and dusk).
- Keep mosquitoes out – Use screens on windows and doors and fix any holes.
- Dump and drain standing water – Mosquitoes breed in still water, so empty buckets, tires, birdbaths, flowerpots, and other containers regularly.
- Use air conditioning – When possible, keep windows and doors closed.
Reporting Mosquito Activities:
If you notice an unusual number of mosquitoes or mosquitoes that bite during the day, contact your local mosquito control agency:
- In Stanislaus County:
- East Side Mosquito Abatement District - (209) 522-4098
- Turlock Mosquito Abatement District - (209) 634-1234
Reporting Dead Birds:
Dead birds can be an early warning sign of West Nile virus in your area. Report them to the California West Nile Virus Dead Bird Hotline:
At 1-877-968-2473 or westnile.ca.gov
