Carla B. Hass



El Dorado County health officials today received confirmation that the County's first human case this year of West Nile virus infection reported near Placerville.  

To date, West Nile virus activity has been detected in 26 humans in 12 California counties. El Dorado County announced the first bird-positive case this year on August 2, 2023.

West Nile virus can be transmitted to people through the bite of an infected mosquito. Mosquitoes get the virus when they feed on infected birds. The illness is not spread from person-to-person. While most people infected with the virus show no symptoms, some may have high fever, severe headache, tiredness and/or a stiff neck that can last several days to several weeks. The infected County resident is recovering from the infection.

Mosquito surveillance programs are in place throughout the County to reduce the spread of West Nile virus. Activities include trapping and identifying mosquitoes, treating neglected swimming pools, and reporting and testing dead birds. Medical providers are required to report all cases of West Nile virus to the El Dorado County Public Health Division, which will coordinate with the Environmental Management Department to investigate the geographic area (if available) for surveillance activities.

The following tips are given to help prevent West Nile virus:

  • Drain standing water around the property and keep water in swimming pools, ponds and water troughs circulating or treated with "Mosquito Dunks" or mosquito fish.
  • Apply insect repellent that contains DEET or another approved substance (e.g. picaridin, oil of lemon eucalyptus or IR 3535) on exposed skin when outdoors.
  • Dress in long sleeves and pants when outdoors among mosquitoes. Mosquitoes are most active at dusk and dawn.
  • Make sure doors and windows have tight fitting screens, kept in good condition.
  • Report dead birds and tree squirrels to the State West Nile Virus hotline at (877) WNV-BIRD (877-968-2473) or online at
  • Wear gloves and place the dead bird or squirrel in a double plastic bag if you dispose of it yourself.

Mosquito problems and neglected swimming pools should be reported to the Environmental Management Department at (530) 621-5300 on the West Slope or (530) 573-3450 in South Lake Tahoe. Additional West Nile virus information can be found at or





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