West Nile Virus

West Nile virus is a mosquito-borne illness that can affect people, horses, and birds. It spreads through the bite of an infected mosquito, which becomes infected after feeding on birds carrying the virus.

• No vaccine or cure for humans.
• Vaccine available for horses.
• Most human cases are mild, but about 1 in 150 can lead to serious or fatal illness.

Symptoms

• 1 in 5 infected people will have fever, headache, body aches, joint pains, vomiting, or rash.
• In severe cases, people may experience encephalitis or meningitis, possibly leading to death.

Prevention

• Use a insect repellent with EPA-registered ingredients like DEET, Picaridin, IR3535 or Oil of Lemon Eucalyptus.
• Wear long sleeves and pants.
• Eliminate standing water.
• Avoid outdoor activity at dawn and dusk when mosquitoes are most active.

Placer Mosquito WNV Response

The Placer Mosquito and Vector Control District is actively working to monitor and reduce the spread of WNV:

• Mosquito surveillance: Testing mosquitoes throughout the county.
• Public education: Sharing tips on prevention.
• Treatments: Targeting both mosquito larvae and adults.
• Community help: Reporting dead birds and protecting yourself is critical for early detection.

How to Report Dead Birds

Report dead birds online by visiting the California West Nile Virus Call Center or calling 1-877-WNV-BIRD.

2025 West Nile Virus Activity

California West Nile Virus Reporting

More Information

Visit westnile.ca.gov for statewide reporting, current data, and additional resources.